The Liquid Edge - All About Technical Diving

Medicine and the Technical Diver

2009-03-30T17:03:00.006+02:00

By Gerhard du Preez.

It is a human trend to grab for medicine any time a problem is perceived with regard to their health. Divers are no different! We self medicate for something as simple as a blocked sinus (which prevents the diver equalizing properly) to something as common as seasickness, never mind drugs required to compensage for muscle aches and pains from the lugging heavy cylinders or over doing it in a current.
But are we really paying attention to what we put into our bodies ? The Technical diver is even more prone to the horrible side effects drugs can produce during a deep dive. These side effects are affected by depth, longer exposures and higher partial pressures of oxygen. Did you know that some of the drugs for prevention of seasickness for example contain a very high dosage of an ingredient that is used for sleep medication and is at almost the correct dose as prescribed for insomnia! Now you go diving on that, dealing with narcosis and all sorts of fun side effects start to kick in and complicate your dive.

Speaking to your GP is usually not the best answer - you must discuss this with a diving physician that actually understands what an increase in ambient pressure does in combination with excessive exposure to Oxygen.

So what to do until you get that brilliant opportunity ? Well, there are two specific things I want you to look at, the sympathetic and parasympathetic nervous system and their response to drugs and diving. These are the most important systems when it comes to predisposition to oxygen convulsions and of course narcosis and mental slowing. My advice is to read the pamphlet that came with your over the counter meds for a change!

What happens when a drup affects the sympathetic system ? The sympathetic nervous system is in essence the “ fright and flight” response that puts the body under strain as it immediately prepares the body to go into self defence mode. The heart rate increases, breathing rate increase, pupils dilate to let in more light so you can see better, blood get channelled from less needed organs to the vital ones, brain, heart, kidneys etc. The result is a dry mouth as saliva secretion takes a back seat as there is no need for gastric juices to digest food at this point. When a drug affects the sympathetic system you as a diver can expect to suffer a severe increase in susceptibility to Oxygen Toxicity and the all feared oxygen convulsion. Avoid drugs that STATE : Increased heart rate, increased blood pressure, dry mouth, photophobia, tremors etc. Especially do not take it if it clearly states “ do not operate heavy machinery while taking this medication” . It is a tad stupid to put it mildly to go diving with any drug with these types of side effects after reading this. These are very, very common side effects and every diver should be aware off them and NOT use those drugs.

The parasympathetic system is what I like to refer to as the “ stay and play” one. The body prepares to basically go to sleep or shut down which is the reverse of the sympathetic nervous system. Your central core relaxes, the heart rate goes down, breathing slows down, more gastric juice gets excreted, pupils constrict and become smaller as the body starts going into energy saving mode. This fits the category of most antihistamines and especially seasickness prevention medication (stuff like dephenhydramine etc). So look for side effects that cause drowsiness, dizziness (usually associated with the fact that you blood pressure is dropping), an increase in salivation etc. Meds that you suspect are affecting the parasympathetic nervous system increase narcosis and when diving with high partial pressures can result in blackouts.

OTHER INDICATORS : There are a few more side effects that warrant mentioning.

- Drugs that have anticoagulation properties (like warferin that thin the blood) will cause excessive bleeding etc.

- NSAIDS ( non steroidal anti inflammatory drugs). Those brufens you are popping cause an increase in blood pressure so be careful as the immersion effect already causes an increase in you cardiac preload and thus your blood pressure.

- Drugs that cause an increase in urination frequency, including and not limited to blood pressure control medications. These will increase your risk in DCS. And the list goes on.

Thus in summary and as a rough guide, if you are unsure ask the pharmacist if the drug has any effect on the sympathetic or parasympathetic nervous system, if the answer is yes, then do not use it prior to diving.

Before I finish, I would like to give special mention with a suggestion of an alternative medication:
- Decongestants – rather try a nasal spray as it is more site orientated and not as systematic in action.
- Sea Sickness prevention- Ask your doctor about epanutin, a drug prescribed mainly for prevention of epilepsy that was found to be very effective against sea sickness.
- Anti-inflamatories, antihistamines and other substances need to be used in moderation. Think if it is really warranted or could you rather do without for now.

Remember this is just a rough guide to assist you in making a quick decision when looking at the drug solely from a diving safety perspective. Do not stop using any chronic medication without consulting your doctor.

Safe Diving

Rebreather Cells - the Saga Continues

2009-01-07T15:10:00.007+02:00

Welcome back and I hope everyone had a fantabulous new year! We had a brill time...and learnt that snorkels are CRITICAL gear. Yes, we found the wading depth of my Ford F250...and then spent a fascinating 1.5hrs finding out where the water went and how to get it out! With beer, a stunning river view, hippos and thankfully no lions. But back to diving :). Gerhard has this to say:
I have had a few comments after a recent article published in a local diving magazine in regards to the "rolling" of cells for re-breathers.
You need to understand one thing. In my opinion if the manufacturer recommends something then it might be a good idea to follow the recomendation, regardless what your own opinion on the matter may be. If for no other reason than the fact that they built the unit and therefore know a whole lot more about it than any diver could (no matter how many hours have been spent on the machine).

Rolling (of the cells) is an old concept that tech divers have been implementing not only with cells but with other bits of gear as well. Back before equipment was reliable (ok, so that statement may still stand the test of time) we used to "roll" everything from flashlights to batteries.

For example , I dived a backup light from 2 different brands, the batteries were from different manufacturers and were changed prior to any hectic dive or after any dive if they were found switched on or if used simply because reliability on these items was questionable. Reliability is the very reason I do not use re-chargeable batteries in my re-breather controllers - they have a different voltage curve and you can get into trouble. Instead i use alkaline or lithium type batteries.

Interestingly enough we teach our students to roll their controller batteries but yet advocate not to roll the most questionable part on the unit - namely the cells ?!? Sheesh. If the batch has a fault you just shot yourself in the foot and yes there have been some batch issues. You never know how that cell was stored up to the day you got it. It is considered to be the most unreliable part of your unit and also the most important one in regards to staying alive.

To my knowledge the following manufacturers advocate very publicly and loudly that you roll your cells:
- Juergens Marine (Hammerhead), Dive Rite, AP Valves (Inspiration) as well as Megladon.

The choice is yours. Get cell validation or get true voting logic but the only way to achieve it is to roll the cells as the parameters will be different when compared to replacing all the cells all at once ...... and having what is called a "false positive" that might just make your 3 horses turn out to be 3 donkeys.

Keep safe...and keep diving :)

Blending Roles and Responsibility

2008-12-10T10:20:00.005+02:00

Recently we heard yet another blending horror story. A rebreather diver dropped his oxygen cylinder off to be refilled on site, picked it up and decided to check the contents... to discover that it had been filled with 50% oxygen and not 100%. A potentially fatal mistake. He did the right thing, he analysed his gas...but too often divers abdicate responsibility and just assume that the blender knows what they are doing. They trust their lives to someone else...which is something I have an issue with.
So, what are the roles and responsibilities between diver and blender ? The rules and regs are simple enough. The diver is responsible for analysing his gas when he receives it. The blender is responsible for ensuring the person filling has completed an official blending course (including the exam) and that the diver signs for his gas.
The problem is that we all get to blase about it...and stop following the process. It is a pain for the blender to complete a log, the divers complain about the delay... and invariably blending is delegated to a low ranking employee who may or may not have the proper, official qualifications. All round it is a disaster waiting to happen.
Diver do not make it easier either. We had the instance the other day with a new client arriving to have Trimix fills. It was a bit of a last minute thing (as it somehow always tends to be). When Gerhard examined the tanks he discovered they did not have any markings indicating that they were oxygen cleaned. G phoned the client asking what the status was. The client was a little annoyed... what was the problem ? G explained that we do not fill cylinders without oxygen cleaning and if we do not know the tank, we will oxygen clean them ourselves to make sure. His reply, what is the problem ? It is only a small amount of oxygen you are adding. I started to have a small fit. Why ?
Well last year we had a small oxygen explosion, from a cylinder that we knew and trusted. Gerhard walked away slightly deaf and with a nasty burn on his arm. Did I mention that this was a cylinder with all its paper work and a diligent, trusted owner ?
The long and short of it was that the client was told that if he wanted us to fill his cylinder he would have to get them oxygen cleaned, either by us or someone who was qualified. For some reason he battled to grasp the concept that his R40 nitrox fill (ok, there were some more expensive trimix fills as well) was not worth Gerhard's life. And that is really what it boils down to.
As divers we do not want to be bothered with rules and processes. So here are a couple of things you can do to make the system work

1) Have your paperwork. Cylinders that are nitrox filled or trimix filled need to be oxygen cleaned by a reputable vendor

2) If your cylinders are filled at the coast they require an oxygen clean before you fill them with nitrox or trimix again. In fact, if you are filling with any sport shop you should get them oxyen cleaned before using them for mixed gas again. Simply put, clean gas is not easy to find and it only takes a small amount of oil to kill the blender.

3) Give the blender time to fill your cylinders. It can take 2 hours to do a Trimix fill and the more rushed the blender is, the more chance for errors

4) INSIST on signing for your mixes when collecting them from the blender and ALWAYS ANALYSE even if it is pure oxygen. If the blender is reluctant for you to sign remember he is legally bound to perform this check and if he still has no mechanism in place... create your own paperwork. If something goes wrong on the dive the first thing that will be examined is the mix in your cylinders... and it starts to get ugly when fingers are pointed at the person who blended...you... the person who placed the cylinders. So why not avoid the whole ugliness/

5) Take your own life seriously. Is it worth R40 (a nitrox fill), R500 ( a trimix fill ) ????

Gulp

2008-12-10T10:17:00.003+02:00

Apologies. I suddenly realised it was the 5th of November last time I wrote on the diving blog. Firstly, a question for ya all...what questions do you have that you would like answered (preferably on technical diving). We do have some items scheduled for the New Year starting with a look at the different gases...

Lastly, I would like to wish everyone a spectacular festive season. We are off to the bush for three weeks and the blog will resume in the New Year.

May the bubbles be kind to you :)

The Skinny on Disinfectants

2008-11-05T10:23:00.000+02:00

This blog is for those of you on rebreathers! Historically in South Africa we use Buddy Clean to disinfect our machines, the question is, is this the best choice ? I have taken the content of this blog from the ANDI manual on rebreathers. Their content in turn is based on a study conducted by the Department of R&D, Canada in 2002.
The study had two criteria that had to be met for a product to be recommended for use:
1) The product had to exhibit an absence of components that would case undue risk to human health during use that could not be prevented by reasonable protective measures
2) Proof had to be available that the disinfectant was effective
Interestingly, the report showed that 7 products commonl used were unacceptable. These were:
- Buddy Clean (gulp)
- Confidence Plus
- Sanizide Plus
- Advance TVE
- Bi-Arrest 2
- Cavicide
- Listerine Antiseptic
Only two products were found to be fully acceptable, Virkon S (the product of choice) and Trigene II. Unfortunately at the time the study was released there was no version of Virkon available for human use (its origin is agriculture). There is now Virkon (without the S)
Some info on Virkon:
- It has been extensively tested and proven tot be a broad spectrum disinfectant, considered bactericidal, virucidal (both enveloped and non-enveloped), fungicidal and a tuberulocidewhen used at its intended working concentration of 1% for a min soaking time of 10 minutes.
- It comes in a number of package sizes.
- It is no deactivated by detergents or hard water, but may leave a residue if recommended decontamination procedures are not followed
- If used as prescribed, it is not deleterious to the health or equipment of divers and is effective against almost all microorganisms to which a diver may be exposed.
- Extended soaking of metal objects may cause corrosion/ damage and deactivation of the product more quickly (recommended soaking time is 10 minutes).
- A 1% solution is table for a week.
- Good infection control practice indicates that disinfectant solution should be changed daily, but this is unnecessarily wasteful. If the solution loses colour within the subsequent 7 day period it should be replaced
Interestingly ANDI and Juergensen Marine recommend a standard solution of 1% beta-dine solution for disinfecting.
If you are looking for alternative, here is the list recommended by ANDI (in order of preference)
- Virkon
- Virkon S (the agricultural version)
- Trigene !!
- Microban Disinfectant Spray (an ANDI product)
- Commercial Hospital Use disinfectant solution such as Beta-Dine 1
- Buddy Clean
- Alcohol
- 10% Bleach Solution
- 50% Vinegar, 50% water
Based on these findings, Liquid Edge is importing Virkon and it is way more affordable than our usual products. Try one tablet that makes 0.5 litre for R30!

The Truth About Cell Calibration

2008-10-24T10:21:00.002+02:00

This is written by Gerhard...for all those rebreather divers out there (and especially those who have been following the recent reported, alleged, near death on an inspo). If you have any questions....mail G at gerhard@tekdiver.co.za :)

First things first: cells becoming current limited is a huge reality, can happen for sure! Remember they are one of the weakest links in your re breather. So what to do....

Looking at how the unit calibrate:
When you hit the "yes" button, the display you are looking at is the milivolts divided and measured against air in Oxygen. So to give you an example , one for altitude , one for sea level.

Sea Level: assume ambient 1 bar. Air= 0.21 , O2= 100% Calibration starts and the displays read : 1.02 1.00 0.96 What the unit does now is compare the mV reading to air whilst being in O2 , thus ACTUAL mV will be the following:
1.02 will be basically 10.2mv (thus the inspo now uses a set MV for start calibration assuming about 4.7- 021/100% oxygen- as its linearity checking) so the real MV of the cell submerged in O2 will be 10.2 mV * 4.7 = 47.94 MV , and that would ASSUME the start up MV was 10.2 as well ( It assumes Cell linearity is constant) NOW if you kick the lid off and measure cell 1 with a mV meter and do NOT get a reading of 10.2mV in air.... oops then the assumed linearity is incorrect....more about that later!

The Cell should be kicked out if it falls below 8.3mv approx (39.01mV)

The Hammer boots out ANY cell that does not make 40mv actual as it is predicted to become current limited(including at altitude ,which is a
bugger)

At altitude the same applies EXCEPT that you must take the MB reading into
context:
Thus if your reading is 0.89 0.88. 0.91 at altitude with a 850mb reading then just multiply the resultant by 0.850 to take it to "altitude"
Thus cell on will be 8.9mV * 4.7 / 0.850 = 49.2mV SEA LEVEL , or 41.83 Altitude reading- good stuff.
So even if you do not see a 1.00 when calibrating at altitude it does not mean the end of the world. According to your altitude it should be fine (above 40mv) SO if you work out the actual MV and see it is below 40mV actual for the altitude regard it as suspicious

NOW what I do NOT like is the fact that it works on a constant linearity assumption when you calibrate( 100% / 21%=4.7). So if you look at an actual as in the hammerhead you have the following:

At sea level my cell mV read in air : 10 9 9 After dousing it in pure O2 for calibration they all stabilize at 39 48 43 mV respectively.
That means that the ACTUAL linearity is as follows :
Cell 1 - 3.9
Cell 2 - 4.8
Cell 1 - 4.3
Thus you can see that it is NOT an actual constant and also cell 1 that seems high did not actually make the calibration and is now booted out as a possible limited cell, but the inspo will calibrate this cell as acceptable (borderline but there) esp if you told it the O2 content was 98%......

At altitude I expose the head to air to see the PO2 shown to verify air:
The mV reads 10 9 9
The Po2 I expect to see is .21 * 0.850 mb = 0.178 PO2 actual that the handsets should display.
All cells displayed within that range since previous calibration.
I wrote down my mV in Oxygen from the previous dive which was 39 48 43
respectively.
Thus at altitude with pure O2 I expect to see a PO2 of 0.85 shown for each cell.
They all get very close to it.
You can then look at the linearity from each cell then vs now.

So cell 1 is 39/10= 3.9
Cell 2 is 48/9= 5.3
Cell 3 is 43 /9= 4.7
If you calibrate now and all values are still within that linearity level the cell is shown to be constant within calibration range. So if you DID fitness test the cell on the previous dive at 6m and it passed and now linearity check and mV seems stable the cell in theory should not be a problem as it's linearity range did not change (you can only hope!)

Also , in theory it also this tells us is that the cell showing highest linearity should be the most accurate in response range as it can read over a finer scale , no it does not mean it might not be limited, it just tells me the response range is the widest. It is like looking at a 300bar gauge vs a 400bar gauge. The 300 bar gauge will show clearer needle movement across the board as it uses a finer scale. You can see 2bar movement more clearly on the 300bar one than on a 400 bar gauge. So I would expect cell 2 to react nicely during flushes and O2 additions with cell one maybe a bit slower.

Use an approach where you can see yourself what the actual mV in air and actual PO2 is in air in regards to the previous calibration, and once the unit or cells are flooded with O2 then you can record that mV and PO2 shown BEFORE calibrating again. If the linearity is within the same limit the cell should perform in the same fashion ,esp if it is a few months old. You will at some point have 3 new cells in your unit ,it is unavoidable sometimes , but they need to be checked vigilantly esp in the first month. The hammer you can also leave flooded with O2 and come back after a while and look at the ACTUAL mV of the cells to see if there is any deterioration in the actual voltage. If there is , flood with O2 again, if the cells do not come back to previous max mV then get worried! The only way to test if it is current limited is to actually pressurize the unit on the surface or dive to 6m then spike it, deeper would be great. Problem is you do not want to start a heavy dive with an O2 spike through the lungs;-) But you can always go O/C , flush at 8 or so meters while manually manipulating the lungs to try get O2 cycled , look at the readings , then flush again and get on the loop and continue the dive.

Now this all sounds very good , but lets get back to the BUT... There are two options, one is single point calibration- so we use high o2 or 100% O2 to calibrate the cell, OR we try 2 point calibration, so we assume x linearity in air and x in O2 and draw a line, sounds good...and here is the BUT. Cells are NOT linear, they have a curve! The further away the maximum or minimum extends the worse the curve slopes, so your most accurate reading is the CLOSEST POINT TO CALIBRATION. In other words, if you calibrated at sea level- Po2 1 - then your most accurate readings should be in the 0.7-1.3 vicinity, if you calibrate at altitude- Mb 850- then all cells read Po2 0f 0.85.... hmmm...then reaching 1.3 is that little bit harder... Remember cells are usually within 2% error margin of calibrated value, so the only solution to check high end readings is to test the cell in a hyperbaric scenario. 2 Point calibration is not helpful either as I showed you with the hammerhead cells in air and O2 as the actual linearity differs, and as explained on a single point calibration you have a higher reference point from which to work, thus a smaller error margin...wow..!

Next option- Have cell verification like what was designed for the new Cis
Lunar- For those who do not know: It has only 2 cells ,one is the master and has a pure O2 and a diluent (air) injector close to the cell face. Approx every minute the handset hands control over to the slave cell and test fires a small amount of O2 at the master cell and a small amount of Air, it then looks at depth and if the cell does not show correct Mv for the depth the dive is aborted, so a constant hyperbaric test while diving, VERY cool...
except.... when testing was done on various other units ,they found that when blowing on the cell face you are faced with a few issues : If there is condensation on the cell face it sometimes helps to decrease it (yay!) , OR it actually blew moisture past the membrane into the cell causing.... yes you guessed it horribly incorrect readings. And guess which one manifested itself the most ? The latter of course.

The second fun problem (had one of those) is when you get a cell stuck. That basically gets a layer of moisture onto the cell face, it traps O2 behind the water ,and the cell only sees that O2 reading ,which is usually
setpoint. Now the computer sees 1.3 1.3 1.3 while you are happily
breathing the loop down and die embarrassed...or finally, when the O2 behind the cell face gets metabolized then it will fire the solenoid... oops, hopefully you are not an idiot and do realize when your solenoid did not work for a while, or your lung volume breathes down etc... The cool thing is if it was close enough to fire the solenoid before it got stuck it might be within range to start firing and of course will not stop firing the O2 in as the cell cannot see it... he he.

So what to do.....

IMHO ,only other possibilities :Nr 1= FLUSH YOUR UNIT OR GO O/C if you think there is a problem!!!!! The ONLY reliable piece of hardware is the thing between your ears we all assume is a brain ;-) Roll cells over (BEST), if you passed a fitness test on the cells within the previous 24hrs they should be good in theory, buy a cell checker from Narked at 90 (not really worth it-can built one way cheaper- 600 Pound Sterling!) or start diving at the setpoint where calibration passed (yeah sure!) Check your cells and record linearity if possible, but as stated that will just help you to identify if a cell seems to be performing in the same fashion as the previous dive, and where to expect a slow or fast reaction. The chances of loosing 3 cells to current limitation at the same time is VERY slim indeed! But be careful of exposing and leaving the cell in excessive heat or freezing it. Use a system that independently calibrates the cells and does not "take "readings from another. Use a 4th cell if possible.

In regards to cells, AP always claimed a better and more stringent protocol when verifying their cells, seems there might be a small hiccup. AI ( Analytical Industries) makes most of the cells. I have had as many AI cells fail as PSR cells as AP cells. Once again. Roll cells over, check linearity yourself for interest. You can clearly see how an assumed linearity can produce interesting readings. Just use bit of common sense and remember :
the job of the re breather is TO KILL YOU! Your job is to make sure IT DOES NOT!
If you weren't confused before , I hope you are now ;-) Cheers for now.

The Argument for Rogue Agencies

2008-10-14T11:59:00.000+02:00

The chat group has been wild over the last week or so (I did not pick up mail for 4 days and had over 80 mails sitting there). What jumped for me was a reply from one of the agencies about how they had trained all of the divers listed as ‘heroes’ in one of the responses. Now my name was on that list of heroes and I found myself with a sudden resistance to an agency laying claim to ‘glory’ just because I happen to have a certificate from them. The main argument was on creating divers with the right attitude and the agency in question was ( I guess) trying to imply that they create divers with the right attitude who become role models in the community (nothing like a blatant plug on an impartial chat site). Which just stuck in my throat. Is attitude created or is it something that was there all along ? And if it was created, by who ?
I doubt the answer is simple. Good divers start off with the ‘right’ tendencies that a ‘good’ community will re-inforce. Conversely, bad divers will be influenced by the community in which they find themselves. And there is that word again, community. The diving community is a complex animal, made up of divers, equipment suppliers, dive sites, operators and of course, the agencies. They are all interlinked, but some have more influence than others. A dive site/ operator that does not enforce standards by banning rogue divers creates an environment where there are no consequences and so allows other divers to start breaking rules. Their influence depends on the number of options out there, so dive sites have more influence than say a dive operator who has to compete with a number of similar operators and so is probably less inclined to be concerned and drive away paying customers. Then come the divers themselves, who get to choose to stand up for standards and make it known when they are broken and that it is not OK to do so. Their effect is also variable and often creates cliques of like minded divers who are hard to break into. Finally come the agencies. Now, as an agency your job is to create skilled divers. These divers become your brand, your face out in the world if you will, which implies that an agency should be carefully monitoring its divers and ensuring that they are in fact representing the right image. One would expect that agencies (both sport and technical) would pro-actively discipline its divers and instructors when they flagrantly violate the rules and standards. But they seldom do which creates an impression that (once again) this behavior is condoned. The result is that we have created a community where there are simply NO CONSEQUENCES.
So I was pleasantly surprised with ISDA. For those of you not on the chat list, this is a new, local agency that has received a lot of flak for breaking away from the older, more established agencies. It now has the unenviable title of being a rogue agency. Johan Beukes (a controversial figure in himself) decided that he was fed up with the lip service being paid to standards and to the poor quality of diver that was being created by our locally established agencies (both sport and technical), so he created his own. The recent incident where a sport instructor took open water divers on what is a full Cave, Trimix dive saw the usual blame shifting… except for ISDA, who suspended the open water diver who did the dive! In fact, they recently suspended an instructor for taking experienced open water students to a mere 40 odd meters in open water. ISDA divers know that they are their agencies brand and their agency is serious about its standards. They now know that if they break those standards there are consequences, which means that there are probably going to be a whole lot less standards being broken by those divers. Which leads me to ask the question, isn’t it time that the old, complacent agencies started to catch a wake up! Here is an agency that takes its standards and reputation seriously. Here is an agency that understands that its reputation is based on what their divers actually do AFTER the course is over!
I find myself asking the question, should I be paying more attention to ISDA and getting involved ? It would blow my neutral stand completely….but maybe it is time to stand for something, rather than against something.
We are the diving community ! Who you are and the service you demand from agencies and dive sites is what has created and what will create the community in which we dive. If you want to improve the standards out there, you need to commit to creating an expectation of action from the agencies and an expectation of compliance from the divers. And while that happens, I am going to start paying more attention to those so called rogue agencies!

Wondergat Fatalities

2008-10-08T10:12:00.002+02:00

These stats are compliments of Mike Beresford, a fellow WUC (Wits Underwater) diver and long time friend...... Total Number Counted to date - 13.

1971: A diver from Wits Underwater Club died after a free ascent. The diver was using a cylinder with a reserve valve (J-valve), and no SPG. The J-valve usually had an actuation rod / pull rod down the side of the cylinder, to allow the diver to pull the reserve lever. In this case the diver did not have one, and was unable to access the reserve. He tried to do a free ascent, but suffered from pulmonary barotrauma. I spoke to Roly Nyman about this one years later, and he added a detail that is quite relevant to divers even today. The victim had done many dives with the cylinder, without the reserve rod, and always been able to actuate it. On this particular weekend he was diving in a brand new wetsuit – apparently a birthday present. The wetsuit was far stiffer than his old gear (probably a thick rugby jersey, knowing the times), and on this occasion he was unable to trigger the reserve. Even small changes in equipment can have a major effect. Don't take untried equipment on a deep dive.

1975: A diver died during a club trip with the Transvaal Sub Aqua club. I was later a member of this club, and had access to all the old records. I also spoke to older members about this accident, but no-one could shed much light on what actually happened. The diver had been trained overseas, in Germany, and had never dived with the club or in South Africa before. He was also suffering from flu at the time. The club Diving Officer advised him not to dive that weekend, both because of his condition and because the DO was not happy with his training records. The diver decided to go anyway, and the club took a “it’s your risk” approach. Afterwards this was a major discussion point at the club, and the committee minutes in the aftermath note that the club would, in future, be more “positive” in controlling who could and could not dive. In terms of the actual accident, it appears that the victim lost consciousness and drowned. Whether it was narcosis, medical, or a combination was uncertain.

1977: A bad year at Wondergat. Early in the year a diver from Eskom Sub Aqua died. Again the details are not too clear, as he separated from his buddies. His body was later found on the bottom.

Later in the year two divers from Wits Underwater Club died on a night dive, Wondergat’s first double fatality. The divers had been doing a shallow night dive , using a line and float to keep them at a safe depth, and out of overhangs. The club also had a surface marshal, logging each group in and out. The two divers surfaced after the dive, a few metres from the entrance. The surface marshal logged them as surfaced, but then some time later noted that they hadn’t climbed out. There was no sign of them at the water, or at the camp. A search was launched, and the bodies were recovered from the bottom. According to the theories on this accident, the two divers decided to swim underwater from where they had surfaced back to the exit point. However, on descent they managed to pull the surface float underwater, and ended up going all the way down. Inexperience was certainly a factor in this accident. It is also important to see how the systems they thought would protect them proved inadequate.

1983: The Niewenhuizen twins. Probably the most talked about accident at Wondergat. The twins were on a night dive, linked by a buddy line and with a single torch between them. At some point they separated from the group, and lost the single torch. The torch bobbing to the surface was actually the first sign that the rest of the group had of the problems. The bodies were recovered from the bottom the following morning. Although there was a lot of criticism of the dive group for allowing two divers to share a torch in this manner, it was not an uncommon practice. My first night dive at Wondergat two years before this was in exactly the same situation! It was only after this that it became an absolute rule that each diver had to carry their own torch.

1984: A diver died after becoming entangled in a rope near the grid during a night dive. I never got many details of this accident, as it involved a dive school at a time when there was tremendous animosity between schools and clubs. The dive school later denied that there had been an accident, my only lead was that I knew the divers who did the body recovery.

1985 or 1986: A diver from the RAU club died in the main cave. Again many details were unclear as the victim had separated from the rest of the team. His mask was found some distance from his body. There was speculation that he’d lost his mask, and tried to do an ascent with his eyes closed, or at least with minimum opening. He is thought to have hit his head on the cave roof and lost consciousness as a result. Nuno Gomes and Malcolm Keeping recovered the body.

1991: Dick Grace incident. A very experienced instructor (Instructor Trainer) was killed during a deep rescue. I haven’t got the full details, I was living in the UK at this time and only heard about it much later. As I recall a student also died. The whole dive was basically a mistake – inexperienced divers being taken too far. The fact that the leader was a very well experienced and qualified diver didn’t prevent the accident, the leader was killed trying to rescue one of the victims.

1996: A free diver died, presumably from breath-hold blackout. He had been free diving to the bottom of the main shot line, was seen to surface and then immediately sank. Sadly this took place right at the end of a weekend, so all scuba gear had already been packed away. By the time a team could be kitted up and sent down, it was too late. Despite lengthy resuscitation efforts, the diver died. The diver in question was very experienced, but perhaps showed poor judgement by free diving so deep with no cover available.

2004: A lady diver died during a dive. From what I could gather, the victim had a medical problem that resulted in her losing the regulator. She subsequently drowned before she could be rescued.

Diving Deep on Air

2008-10-01T13:06:00.004+02:00

Last weekend a young sport instructor (who only recently completed her Advanced Nitrox course), deemed herself fit to take an even less experienced diver (open water 2 I believe, so what, 20 dives ?) to the back of the cave at Wondergat. This is a cavern dive to 52 meters. It looks easy. First you descend 35 or so meters to the cave grid. Then you head off on one of the permanent lines, down a fairly sleep slope that slowly levels out as you enter the gloom of the cavern. If the vis is good you can see the whole cavern mouth from the back. Normally the vis is trashed thanks to inexperienced sport divers speeding in on short bottom times (to avoid decompression) and with inadequate buoyancy skills.

This is not the first time that this instructor has done this. Last time a complaint was lodged with her agency (nothing happened) and she was talked to by experienced technical instructors so I can only conclude that she sees nothing wrong with her actions and deems herself to be a superior diver that can manage any situation at any depth with any number of following divers. This is interesting because one of the fatalities from the back of the cave was a highly experienced national instructor who took open water 2’s to the back of the cave and paid for it not only with his life but also the life of one of his students (the student was on a single cylinder and ran out of air at the back of the cave. The instructor was on twins. They both ran out of air before reaching the mouth of the cave).

The thing about Wondergat is that it is deceptive. Going in is easy thanks to the slope which means that there is little effort involved. Going out is a swim thanks to that slope. This means divers are having to work, which increases gas consumption… all of which is a recipe for disaster. Especially if the divers are sport divers with marginal buoyancy (yes, pretty much every diver we get thinks they have buoyancy control but turns out when they have to do the standard technical drills they do not), sport equipment (one cylinder, one first stage, no back up gas, no decent lights) and no gas planning. Oh yes, and no experience or build up to mitigate narcoris.

I have a number issues with this dive. Firstly let me point out that this lady is not the only instructor doing this. She was just silly enough to brag about it on the net, so she gets to be the lesson.

My first is the arrogance of instructors who think that they are capable of dealing with the situation just because they are instructors. That is the kind of attitude that has killed people in the past and will kill people in the future. It is called ego and it seems that women are not immune to it. An instructors does not give you immunity or god like powers (and this applies to highly qualified, experienced technical instructors as well).

The second is the blind naivette of the student who believed her and followed her (see my blog on trusting experienced divers). As a diver you need to take responsibility for your own safety and not just trust divers who seem to know better. The odds are they do not! And you pay the price, often with your life.

Lastly, I am annoyed and concerned with the blasé attitude of sport divers and instructors who simply DO NOT KNOW how restricted their world is and break the rules without bothering to find out how. Now I guess that last statement could be deemed to be contradictory. After all, I am stating that I do not condone breaking of the rules (divers should not dive outside of the depth they are trained to) and then I say if you are going to break them at least know how ? Training is one way to learn how to break the rules. It is there to teach you what you do not know and how to to safely extend your limits. It is not the only way to learn however it is the safest.

I should at this point say that there is a reason PADI does not have courses that take you deep…depth changes the rules significantly. Sport diving teaches you to dive on a single cylinder with no decompression. It does not teach proper dive planning, proper gas management, proper buoyancy control and any appropriate risk assessment or management that will allow you to undertake a deep dive safely. Why ?Because that is not what sport diving is about. Sport diving is about the path of least resistance. It is about the least amount of knowledge that will get the most people divin, safely enough to avoid legal action (perhaps a bit cynical, but not so far from the truth). That is why technical dive training exists.

So, why is the back of the cave so different ? And how would a technically trained diver do things differently ?

The first hurdle to get over is the anti-air brigade. It has become kewl to diss air and recommend Trimix. Yes, air is bad and yes, you should be diving Trimix. The problem is Trimix is not always available and when it is, it is ludicrously expensive (think R600 for a dive). Based on these two facts alone, air is NOT going to go away easily. Add to that the fact that air is easy to come by never mind easy to breathe and there is no real hard limit to stop a diver from just going deeper and deeper. Now throw in the handy dive computer and any limits a sport diver used to have disappear entirely. They don’t have to think! They don’t have to know anything about decompression. All they need is a full cylinder and a dive computer and they can go anywhere for as long as they like…… or so they think.

If you are going to dive air you need to understand the characteristics of air and the risks entailed so that you can actively PLAN for these. In a nut shell dive planning firstly identifies what risks are unique to the dive you are doing. Then it allows you to consciously determine if you can avoid these and if not, how you are going to manage them. All dive planning amounts to ensuring you have enough gas to breathe for the whole dive (and never touch your reserve), you have enough light to see by, you have the mental ability to think and that you can manage any probable situation underwater.

For the back of the cave the list has things like:
- Narcosis, it is 50m
- It is dark, and gloomy so if you lose the line you are lost
- It is dark and gloomy, so your narcs is going to be higher as you are going to be more stressed
- It is at least 5 minutes (that is optimistic) from the surface, probably more so what happens if you have a dv failure, or blow an o-ring ?
- It is going to take at least 5 minutes to get there, which means you have descended at speed, which means your narcosis is going to be way worse.

Lets look at narcosis first!
Now every diver thinks they know about narcosis. But what do they know ? That it starts at 30 meters ? What divers tend to be unaware of is that the increase in narcosis with depth is not linear but rather exponential. Narcosis at 50 meters plus is very, very different to that at 30 or even 40 meters. To give you an example - as an instructor with Wits Underwater club I regularly had over confident open water 2 divers who (because they had been trained at 30 meters) had NO respect for narcosis simply because they had never really experienced it ( 30 meters is the start of narcosis so the effects are hard to notice). I learnt quickly that talking about narcosis had not effect. The only time these divers got respect for how bad they are at thinking and ‘doing’ at depth was when they were deliberately taken on a dive designed to narc them out (that would be a fast descent to 35, 40 meters). Then and only then did some (not all ) of them realise how debilitating narcosis really is, which is the point at which they started to take it seriously.

The next thing you learn is that there is no cure for narcosis. If you dive deep enough on nitrogen you will always experience narcosis (adding helium only extends that limit, it does not cure narcosis ). To get rid of narcosis you have to reduce the partial pressure of the nitrogen in your mix, which practically means ascending. Acclimitisation makes a difference. In fact, divers who regularly dive deep air spend inordinate amounts of time training for deep air and acclimatising.

Now the concept of acclimitisation is in itself controversial. I am a deep air diver, so my experience is that if you build up for depth your ability to manage task loading (think and do) is greatly improved. In fact, if I have not dived deep for a while my first deep dive will be a nightmare. I am totally narced, so I spend as little time as possible there and get shallow as fast as I can. The next dive is normally better. My approach to managing high levels of narcosis is to slowly build up to them. What do I mean ? Well if I was to move from 30 meters to 50 meters I would spend a weekend just doing 30 meter dives -. 3 on the Saturday (all with decompression because it is time at depth that gives you acclimitisation) and then a 30 and 40 meter on the Sunday. The next weekend (not more than 2 weeks later) I would then do 4 40 meter dives. Only then would I deem myself to be fit to do a 50 meter dive (and then only if the dive is within 2 weeks of the build up sequence). On the actual weekend I would do a 30 and a 40 m on the Saturday followed by the big dive first thing on Sunday. Oh, and I would have had no alcohol for the entire build up sequence and be avoiding things like caffeine and coke.

There are two other aspects a technical diver would look at, having the right equipment and being 100% familiar with that equipment. Being familiar with equipment means being able to lay your hand on a dv or a cylinder or a fin or a knife within seconds of thinking you need it… without spending valuable seconds searching for it. It takes effort and lots of practice to build up that kind of unthinking familiarity with your equipment.

Which brings us to equipment. From our dive planning we know that this dive is at least 10 minutes, if not 15 minutes long which means gas is going to be a concern. It is also deep, so you are going to be using more gas than on your normal 20 meter dive. You are also going to have to swim, are going to be narced and it is dark and guaranteed as a sport diver that means you have insufficient light (last Time I heard this dive done with one torch between 4 divers), so you are going to be stressed. As a technical diver you know what your gas consumption rate is so you can work out for a 15 minute bottom time (that means leaving the surface, getting to the back to the cave and leaving on 15 minutes) exactly how much gas you are going to need.

You are also not working on a standard 50 bar reserve rate, but on critical pressures (which is a whole blog on its own). In a nutshell your critical pressure is the number on your spg at which you must turn around. If you turn around when your gas content gets to that pressure you have enough gas to get you to the surface and still have 50 bar left. This is completely different to the sport divers who turn around on 50 bar without knowing if 50 bar is enough to get them to the surface. The assumption is it is and in most cases that is true, because they are diving within very tight limits. Another difference is that leaving on 50 bar means you are still using gas to get to the surface and are planning on reaching the surface with 20 bar. We plan to reach the surface still with all our reserve…totally untouched. If you are not using critical pressures (which requires conscious dive planning), you should be using at the very least the rule of thirds, i.e. you breathe a third of your gas mix into the cave and when that is gone REGARDLESS OF WHETHER YOU HAVE REACHED THE BACK OR NOT, you turn around and come back out.\

There is a good chance that calculating your actual gas requirements will indicate that this dive is NOT feasible on a single cylinder. In any event, as a technical diver you always have at least two cylinders with you. There is a very good reason for this and it is called redundancy. The last place you want to lose your entire gas supply is at 52 meters. Now every good sport diver just shrugs and says, my buddy is right next to me…except he is stressed and sitting at 80 bar, so now you have to get two divers all the way out of the cave on 80 bar ? Not a situation I would rate my chances in. Sport rigs also have only one pillar valve, which means if you blow an 0-ring or have a problem with a first stage you lose BOTH dv’s, the octo as well. Not a situation I would like to be in at 52 m with only a novice buddy to look to for assistance.

At the very least on a dive like this every diver should have access to staged gas. They should be carrying it with them or have placed it at the grave stones and then the cave grid and still they should have something with them.

This is the abbreviated version of a dive to the back of the cave. It does not even touch on decompression, just the basics of making sure you are not narced out of your tree and have enough gas to get yourself and a buddy all the way back out again. There is simply no way I could put into a single blog all the information you would need to be able to do this dive safely…which is why we have technical training. It is also why I will strongly berate divers who do this kind of thing. If you take only one thing away from this, let it be this…. It is never what you know that kills you, it is what you did not know…and what you did not plan for…..oh and sport diving is highly, highly restricted and limited.

Getting Started - Kit!

2008-09-22T12:43:00.001+02:00

One of the bigger challenges with starting technical diving is the kit! Gone are the days when a dive required a single cylinder with any dv and a any jacket bc. Technical diving is about leveraging science and equipment to safely extend your limits and that means a whole new look at equipment.
One of the first things we tell people is, do not buy your equipment before the course without chatting to us first. And the reason is not because we want the gear sales, but rather we find that people often arrive having spent a small fortune on kit that is simply wrong. Within a few dives (if not during the course), they find themselves hastily putting their kit onto the second hand market so they can get something more appropriate.

Getting the Basics in Place
This is kit that you should be acquired before anything else.
- At least one dv (there really are only two brands that compete, Scubapro (my preference) or Poseidon which is Nuno Gomes’s preference).
- Two SMB’s (one red, one yellow)
- A long hose for your dv (this means 2.0 meters)
- A wing and a Backplate (try Frog for value for money).
Total additional outlay (excluding the dv) is in the region of 4.5k. Some of this can be rented, such as the wing and backplate, but as harness sizes can be quite specific it is often best to put that on your priority list of things to acquire.
At this stage the dv is not critical, so you can re-use what you had for sport diving. If you did not get around to acquiring a dv, then you can rent until such time as you do get there.

Filling in the Blanks!
Once you have the basics, then you can start to make additional purchases. Obviously the order of purchase is going to depend on your budget as well as your depth goals. Here is mine (in order of purchase)
- Dry suit ( there is no point in having all the gadgets but freezing your butt off doing long dives) (+/- 10k)
- Your own torch/ light (something along the Sartek line, i.e. canister light with 10W HID light head) (+/- 6k)
- Another dv (secondary) and if you do not have a high end dv (yes, I am going to say the word Scubapro here), this must be high end (+/- 7.5k).
- Your Own Twin set with isolation manifold (new +/- 9k)
- Trimix Computer (+/- 16k)
- Better secondary lights
- Proper Fins
- At least two stage dv’s (+/-4k each)
- At least two stage cylinders (+/- 2.5k)
- More cylinders, more dv’s
- Another computer (you should have two)
- A booster for filling helium
Some of this list is easier to rent and most people only add stage cylinders after they have acquired everything else. The most important aspects in my mind are having proper, reliable dv’s (my favourite is the Scubapro MK25 with S600 or X650 second stage, for stages I have the MK2 with the R380’s) and a decent dry suit. These take care of providing you with gas under any conditions and keeping you warm. Dive computers are really nice to have, but…you can (and should) be doing your dives on paper and not relying totally on your computer. I certainly would by a dry suit before I bought a computer.

Many people get put off technical diving because of the long list of kit that you seem to need. However, most of us acquired our kit over time and not all in one go. The bad news is, you never seem to have enough kit, especially if you start to push your limits and do more exploration. The good news….it is totally worth it

Diving Politics...no seriously!

2008-09-18T13:31:00.003+02:00

The biggest complaint that most divers have in technical diving (well, in diving actually) is when will we all grow up ? To put it is a single word, Politics! This instructor is not speaking to that instructor, this agencies is not speaking to that agency, this one is slagging that one off! What is a poor diver to do ?

This came home to both Gerhard and myself with the current AED initiative we are trying to get off the ground! Now, we thought (naively it turns out), that the diving community might all pull together when it comes to safety! Well, yes and no!

First there was the argument from the coastal contingent, ‘Why should they support the inland dive sites ? They do not dive there ! (completely forgetting that the divers that come and dive with them at the sea are predominantly trained inland)’. We weathered that storm and bravely went on, to meet the next issue, ‘Why should I help out, the dive sites should manage safety, they should buy the AED’! Well, that one just blind sided us! Umm, because you are going to look really silly at a funeral blaming the dive site when all it took was one raffle ticket (or 5 if you are feeling generous) and 3 hrs to learn how to use the AED, but hey, maybe it is just me ? Maybe I am the only one that thinks that something’s in life are just to important to leave to institiutions and that you should just get off your butt and take responsibility!

Then it got even worse! Then we all (DAN included) got accused of playing politics! Questions were thrown around about whose name gets to go on the AED’s ? Why are we (Liquid Edge) behind this ? What do we want to get out of it ? Why should money be given to us ? How does he know where the money is going ? What if we steal it ? That one had us stumped! How do you deal with that level of paranoia ? What was even funnier is that the only person who seemed to have an agenda was the individual preventing us from finding a way forward (and I still do not have a clue what that agenda was).

So I got to thinking, what is it about the diving industry that seems to promote petty politics ? Is it because it is perceived to be small and price sensitive, so that means every individual is in a dog eat dog world and has to fight for his piece of the pie ?

Is it a South African thing ? What do I mean ? Well, we all are quite comfortable sitting back complaining about how the crime is intolerable and why does the government not do anything about it, never even thinking that maybe we should let the government be incompetent all on their own.! Why not go around them and fix the problems ourselves ?
In fact, I have this sneaky suspicion that the country dynamics we live in are totally reflected in the smaller communities like diving. Anyone who is part of the scuba list will attest to the amount of cynicism and ‘fight’ that is part of the community! We just seem to be intolerant in general! And it all is personal!

As an individual I believe that who I support should reflect my personal value system, so there are individuals and companies that I simply will not associate with (Zimbabwe is a big one and yes, I know, how does me NOT going to dive Sinoi make Mughabe sod off ?). I have only one real vote and that is where I spend my money and time, so I use it! But here is the thing, that is my choice and I do not expect you to make the same choices! You have the same freedom of association!

Are we really so small and insecure as individuals that we can not see behind the names to the benefits that could be obtained if we just Got Off It! I am now going to get off my soap box! The point really is this, you don’t have to like me to agree that something is worth doing, and supporting a cause is not always about supporting the individuals behind it! We will never get rid of individuals, but we can get over politics! And as individuals we can start to be responsible for creating the communities we would like to live in! We can make a difference. It always starts small!

How Much is Your Life Worth ?

2008-09-09T11:41:00.000+02:00

This weeks blog is rather a sober one. A week ago Gerhard was involved in a resuscitation of a fellow instructor who suffered what appeared to be a massive heart attack. For those of you who do not know, Gerhard is an active paramedic, so the instructor was in good hands. The resuscitation was not successful and we lost a fellow instructor. We would like to send our sympathies to his family and friends as well as the divers who were there with him at the time.
The incident did drive one thing home for both Gerhard and myself - how unprepared we are as divers for a medical emergency. You see, there is a device especially designed for lay people to use to restart a person’s heart. The site did not have one. No-one on site had one and it took the paramedics around 20 minutes to arrive on the scene with one. It is called an AED and it costs R16,500. My question to you all is, when some-one you love or even just know dies, would you not be prepared to pay that price to get them back ? I know I would!
We are now trying to get the diving community involved in ensuring that all dive sites (starting with the inland sites) have an AED on site. You do not need to be a paramedic to use it, that is the point. As a diver it will take only 3 hours to learn on the DAN AED course. Me thinks it is time the diving community got involved and started to look after its own, rather than waiting for the government or some gracious donor to do it for us. So please watch this space. We are putting together a fund driving initiative with Underwater Africa, DAN, Scubapro and Submerge to raise funds to get one of these at Miracle, Bass and Wondergat. If you are interested in finding out more or becoming involved/ donating to the cause please e-mail me at verna@liquidlearning.co.za.

For those of you who are still undecided - here are some sobering facts from Gerhard:

Cardiac arrest is the most common way for divers to die. The most immediate "rhythm" post cardiac arrest is 90% of the time "ventricular fibrillation". The ONLY medicine for it is to defibrillate the patient. In CPR the only real purpose is to help maintain oxygenated blood to the brain to try and keep it alive in anticipation of a defibrillator becoming available. You have to use a defib to cure the patient.
The effect of delaying defibrillation is significant as a positive outcome is DECREASED by approx 7-10% plus for every minute lost. So every minute that passes on cpr we loose approx 10% viability… and that is with PROPER CPR in progress.
What is proper CPR ? Well even paramedics battle to get this to the level’ proper’. Properly performed, CPR has an approx positive bloodflow result of 8-12% in patients. So we are basically 8-12% as effective in moving oxygenated blood around the body as the heart is. Not a great number but very effective in maintaining oxygen to the vital organs. Here is the thing though, a rescue diver’s chances of giving ‘proper’ CPR are not good. In fact, most paramedics arriving at a scene where a patient is being resuscitated do not hold out much hope of a successful outcome (it is not a nice thing to say, but it is the reality, why rush ? the patient hardly ever recovers in these instances). A patient’s best chance is if he has a witnessed arrest (which is what happened in this case) as he then receives immediate professional attention. But without a defib or AED the chances decline rapidly.
The AED or Auto External Defibrillator was designed specifically for laymen where professional help is not immediately available and the patient has suffered a heart attack. The AED can identify some "shock able" rhythms and apply the necessary steps with voice guidance to the operator. It has been used extensively in the US on airports in a massive campaign and they are claiming very good survival rates. It is a course that almost any DAN instructor can do. The AED is virtually "Idiot proof" and has VERY low maintenance - the battery is non rechargeable (in some units) with a shelf life of 4-5 years and an operating time of roughly 50 shocks or 20 plus hours. Once the unit is used, the battery can be replaced at around R300. It comes with single use pads and a bag.
Personally, I am getting one for myself…for my family, for weekends away! We are already carrying Gerhard’s crash bag every where we go! So please, please, please, join us and get involved! Every diver makes a difference.

Getting Started - Which Course ?

2008-09-03T12:11:00.001+02:00

So, assuming you now have picked an agency, how do you pick course and what do you need to get started ?

What do You Need Experience Wise?
Most technical courses require the following when it comes to certification and dives : at least 50 dives, a nitrox certification AND your advanced diver with deep specialty.
In essence technical courses are designed to create stepping stones that take you from the limits of sport to no limits. This means you need to learn:
- Decompression
- How to use gases to optimise decompression
- How to use twin sets
- How to use stages
- How to use a smb (surface marker buoy)
Once these basic skills are under your belt, you can add more advanced skills like cave skills (which really perfect your buoyancy not to mention add a whole new level of task loading….you now have a reel to manage and a light) and of course the planning and extra kit involved in Trimix diving.

The Starting Point – Advanced Nitrox
Technical courses all start from a single building block, Advanced Nitrox - however, whilst a number of agencies have this course, not all courses are equal and by signing up for an Advanced Nitrox you may not be able to proceed to the next level without an additional course. What do I mean ? TDI’s Advanced Nitrox does not include Deco Procedures (which is a separate course). So to be at the same place as the IANTD course you will need to make sure you also include Deco Procedures. To make it more complicated, not all courses have the same name (and as we just saw, the same name does not mean the same thing).

Adding Skills - Overhead
Once you have the basics under control (decompression, twin sets and stages) you can look at either progressing deeper or into cave systems or both.
Cave courses generally come in nice, easy to learn modules and you have the choice of cavern (where you just get used to being in the dark and can still see the light), intro cave or full cave. These courses are not sequential, ie. You can go straight from advanced nitrox to full cave (in fact, one of our more popular courses is the combination of advanced nitrox and full cave). Incidentally, if you are a sea diver and not so much interested in caves, the cave course is the best way to become a wreck diver, giving you the skills to tackle any wreck.

Adding Skills - Deeper
Courses that extend your depth will introduce Helium and may take you in steps from a Normoxic level (where you need a single helium mix that you can breathe from the surface) to Trimix (where you use a number of mixes during your dive). These courses introduce more detailed dive planning and gas management and of course, get you deep enough to find that elusive Coelocanth or explore that wreck(

When to Combine a Course!
In most instances you are able to combine courses and so optimise your time (and of course your money). The one course you can not do in comination is nitrox, that is a pre-requisite that must be in place. However, if you do not have your deep speciality, that can be integrated into the course you are doing.
Depending on your starting point and comfort you can combine:
- Advanced Nitrox with Normoxic
- Advanced Nitrox with Full Cave
- Full Cave and Normoxic

So, when you going to come over to the ‘dark’ side ?

YOUR GUIDE TO THE COURSES ACROSS THE AGENCIES
· Advanced Nitrox (Depth to 40m) (NAUI = Technical Nitrox plus Deco, TDI = Advanced Nitrox plus Deco, IANTD = Advanced Nitrox, ANDI = Level 2)
Note: For Naui you need 25 Nitrox dives to start and 75 dives to do deco

· Normoxic Trimix [Depth to 60m] (NAUI = Trimix Level 1, TDI = Trimix, IANTD = Normoxic Trimix, ANDI = Level 4)
Note: For IANTD and NAUI you need 100 dives (for IANTD this is a discretionary requirement)

· Trimix [Depth to 100 m] (NAUI = Trimix Level 2, TDI = Advanced Trimix, IANTD = Trimix, ANDI = Level 5)
Note: For TDI and NAUI you need 150 dives of which 30 are deco, For IANTD, 200 but (for IANTD this is a discretionary requirement)

Getting Started - Picking the Right Agency

2008-08-21T10:18:00.002+02:00

Getting started in tek requires a number of decisions on the part of a prospective student, not the least of which is, ‘Where to go ?’ and ‘Which agency to choose? ’ Do you go NAUI, TDI or IANTD and what about ANDI ? Which is the best ? Which has the standards ? Which better materials ? Which better pricing ? Which better course structure ? Which is agency is for you and is choosing an instructor as important a choosing an agency ?

Within the South African technical diving community there are few full time technical schools that focus only on technical diving. Some sport schools do have an in-house instructor who can offer a limited selection of technical courses, but their focus remains on sport divers. Mostly technical instruction is done on a part time basis through part time instructors who offer technical training on weekends. This means that courses are few and far between and often take time to complete having to be undertaken over a number of weekends. Indeed, Liquid Edge is one of two full time technical schools in the country and the only company that is not affiliated to a single agency. Which is where we pick up flak, surely we should have picked one agency and should be recommending this above all others ?

Our non affiliation to any one agency has been an active choice on our part. Our aim has been to provide a single point of contact for divers that crosses all the brands and in so doing provides the client with the ability to choose the ‘right’ course rather than the ‘right’ brand. Indeed, a large part of our goal as a company is to promote technical diving as a whole, regardless of who you end up choosing as an instructor, school or agency. This means we are the only school that has experience in technical diving across all the agencies (NAUI, TDI, IANTD and ANDI) at all levels of instruction (from nitrox, through trimix to expedition trimix and full cave). This means that as an instructor, Liquid Edge’s Gerhard du Preez has unparalleled exposure and experience which in turn means you get a holistic view of all the agencies… enabling you to choose the one that fits best for you (rather than the one we are punting).

There is another reason why we did not choose to represent a single agency… because no agency stands out from the others when it comes to actual standards (and standards are the first and most obvious criterion on which to make a choice). Of the list that we represent, there are only two agencies that are proactive about enforcing and protecting their standards – NAUI and ANDI both of whom do not believe in paper instructor cross overs and made Gerhard do the complete course, all aspects (including swims and breath holds). They also require two pairs of eyes on certification. So yes, we favour NAUI and ANDI from a pure standards view point, however there are other aspects that need to be taken into account as well, like existing brand loyalty (PADI and NAUI both generate students that are loathe to leave their brand) and of course quality of service and materials (books, c-cards etc).

Apart from their international standards, every agency has its own particular South African flavour that either adds to or detracts from our image and the quality of the service we provide when we interface with students. So, whilst we may favour NAUI and ANDI from a standards perspective we have to factor in cost (ANDI is more expensive) as well as the course structure (ANDI has more steps to get to the same place … which from a standards perspective is brilliant as you get a seriously competent diver, but it means it costs more and takes longer). Taking out ANDI, TDI, IANTD and NAUI have similar course structures so it takes about the same time to get an equivalent qualification. They also have a similar cost structure. Which leaves us with the quality of the materials and service that is available to us and our clients. Based on these criteria we prefer TDI as their materials are more what the average PADI diver is used to (professional and high quality).

Based on all of this, our recommendation is simple. If you are a PADI diver, then go TDI. If you are a NAUI diver, why change ? And if you are really sold on IANTD, then congratulations, we can provide you with excellent training that incorporates our knowledge of all the programmes in an IANTD format! In fact, when it comes to cave certification there is no single certificate that will guarantee that you can dive in any cave in the world which means that if you have an IANTD cave course you still need a TDI certificate and visa versa.

Indeed, I would argue that it is not so much the agency that creates excellent divers, but the instructor! What an agency gives you is a set of minimum standards that all divers with that brand will have. Good instructors add to the basics of their preferred agency giving you more than what their agency offers.

From the Dive Show

2008-08-19T09:59:00.000+02:00

I promise that I will not cheat this week and do a small dive show feedback instead of an actual blog :)

Firstly thanks to all the guys who came to visit us on the weekend. We were hectically busy and it was really great to meet people who are visiting our web site and our blog. Our schedule is looking busy right up until xmas and I am looking forward to introducing a whole lot of new divers to the amazing world of tech. To follow on from the show my blog this week will focus on getting started with tech (as that was the conversation we had the most J ).
If there are any questions you would like more info on/ answers on please let me know. Safe Diving ya all :)

Fins are Fins are Fins ! Or are they ?

2008-08-05T14:23:00.000+02:00

Yes I know… an entire blog on fins ???? Am I finally losing it ? Perhaps, but then again fins seem to be cropping up in my conversations these days. You see I am a fan of the Scubapro split fins… and Gerhard (active technical instructor and firm believer in Hogarthian that he is) believes in the more traditional jet fins. Now as you may have come to realize, I tend to view all dogmatic idealogy (especially in diving ) with circumspection, so I get totally suspicious when I get told that there is only one fin for technical diving. The burning question is, is there really a fin that is superior when it comes to technical diving ?
It seems that most instructors and die hard hogarthian (and dare I say it, DIR) divers prefer the jet fin. Owning a pair I have to say it can not be a preference based on pure appearance because they look bulky, uncomfortable, heavy and squat. It is basic, basic, basic with a lack of flexibility in the foot pocket that simply screams sore feet. They are also limited when it comes to colour choice coming in black, black or black (seriously, must all technical diving be done in black ? Can we not get a little more adventurous and maybe try something in navy ? Or heaven forbid yellow, green or even yes..,wait for it… pink ?).
The jet fin boasts a design that is at least 30 years old and a philosophy of sticking to the basics and keeping it simple. Being manufactured out of negatively buoyant rubber they are heavy, which is not a bad thing if you are in a dry suit as it eliminates annoying floating feet and ankle weights. Their manufacture also ensures that they are stiffer than most other fins which makes them feel like you are wearing a pair of planks but having said that this rigidity does mean you have far better control underwater. They are almost designed for modified flutter and frog kicks (which as you no doubt know are essential anti-silting techniques). Because they are extra stiff they are much better suited to high current diving (not really an issue for us South Africans) not to mention propelling heavy and bulky (read drag prone) gear through water both of which are a definite plus.
The jet fin also has one other element of design which proponents wax lyrical about, the straps. One of the first lessons I learnt as a technical diver was to tape up my fin straps to avoid them getting caught on lines etc. The irony of which did not escape me when I found myself with one fin caught mysteriously on the line at 152 meters. Truly the last thing I excepted to go wrong on that dive was getting trapped on the line and I ended up with the choice to either cut the line (which I was not happy to do being as I was in a confined space in a silt out… yes, I could use the walls and positive buoyancy to get out but the risk of getting further entangled in loose line was not appealing) or I could leave the find behind. Which I did. I still do not know what it trapped me…but one of these days I will go back and retrieve that errant fin and hopefully find out what.
Which brings me back to straps. The jet fins come with the most primitive straps you can imagine. In fact they remind me more of Sean Connery James Bond diving gear than the gear we are familiar with these days. Firstly there are no convenient plastic clips for getting in and out (which incidentally is how I got out of my stuck fin. I shudder to think of trying to remove that fin without convenient buckle to release). Instead, the strap connections are moulded into the fin. This means that there is no leading edge groove to catch on line. The straps are also arranged in such a way so that the ends are on the INSIDE of the rest of the strap. This presents a perfectly smooth surface on the outside of the strap and clip area so entanglement is virtually impossible. The down side is that they are a pain in the but to adjust, but then again I think I would rather have that problem then be stuck.
To summarise, the benefits of jet fins (the preferred technical fin) are?
- They are negatively buoyant which is ideal for dry suit divers
- They do not have plastic clips so you avoid the situation where you can’t dive cos you have broken a piece of plastic
- The entire strap is designed to present a smooth surface and so avoid catching on anything
- The blade is firm allowing for better speed and less silting using technical finning techniques
The cons are :
- They are heavy and so more work than something like a split fin
- They come in black, black or black (admittedly not a serious con, but still)
- They do not have an easy to release clip which means getting into them and out of them when dressed in layer on layer of warm stuff is a problem, especially in a dry suit that does not have a telescopic torso.

So what are the alternatives ? My favorite fins are the SCUBAPRO SPLIT FINS. Firstly, they are light so you do not have the feeling that your feet have suddenly turned to lead. Secondly, on a straight scissor kick they are fast and effortless (I was seriously surprised when I tried mine out…spent my first dive checking that the fins were still there and being amazed at the turn of speed I could muster). Oh, and they come in something other than black (a nice neon green for starters). They are modeled on nature (specifically the tail fin of a Humpback whale) which is capable of shifting tons of water with a single stroke. And they are fast being designed for speed and minimal effort (features inclide a patented split fin propulsion system; patented drag reducing vents that reduce drag on both the up and down strokes and an extended sole plate to increase leverage and power output). Simply put a split fin is designed to produce more forward motion with less effort using a scissor kick, which is where the problem comes in.
The last finning technique I find myself using in a cave is the scissor kick because whilst it generates speed, it also has too much downward force and so it generates silt and silt is every technical divers demon. I have been using my split fins for a while and so manage to avoid silt… but at the cost of speed which is an issue, especially when you want to do a long exploration and are on a time line. The problem with the split fin is that the lightness and effortlessness comes from a blade that is just too flexible. This flexibility makes for comfort but makes it more work to move heavy bulky gear through the water.

In a nutshell, split fins are :
- Lighter with a more flexible blade which is a negative for technical diving as it makes floating feet worse and means more silt and less speed when navigating heavy kit around narrow tunnels.
- They do have easy release clips (which I am still a fan of) and do come in a variety of colours (yes, colour is important but perhaps not that important J)

The sad thing is that whilst I love my split fins I have moved back to the traditional jet fin simply because of their superior performance with regard to anti-silting and speed. Do I like them ? Nope, not much… yet! But I am sure after a couple of months I will no longer remember the light and pleasant split fins and instead be comfortable with what feels like two small planks that remarkably have the ability (against all appearances) to enable me to turn on a tickey and dive in a silt free world. The good news is that Scubapro makes both, so at least I have that.

Wreck World Record

2008-07-21T13:30:00.002+02:00

I received this in my mail today and thought it would make an interesting posting. You can get the full article from Nuno's web site (www.nunogomes.co.za). The record was to 236 meters done on rebreathers (Ouroboros) on the Milano with a dive to 236 meters. By all accounts it was a well planned dive with intensive support including a dive bell (boy do I wish I had one of those for the last 4 hours of my dives) and a ROV waiting for them. Not sure our South African budgets would stretch quite that far :)
Here is the article Nuno wrote:
Diving history has been made in Lago Maggiore, Northern Italy. On 10th May 2008 three divers, Pim van der Horst, Mario Marconi and Alessandro Scuotto did “The Deepest Wreck Dive”. They dived the wreck of the “Milano” located at a depth of –236 meters of fresh water, the divers used the “Ouroboros” closed circuit rebreather. The logistic preparations for this dive were both comprehensive and impressive. The support by the Italian diving community was total and it included both sport divers as well emergency diving personnel. The dive was planned by Marco Braga, Andrea Cortesi and Fabio Manganelli with the assistance of many other volunteers. An ROV, positioned on the wreck of the “Milano” at –236 mfw, provided a visual beacon for the divers (with its lights), it also monitored the safe arrival of the divers at depth and established visual proof that they had been there. The most critical infrastructure that was available for this dive was a diving bell (fitted with a hot water and surface gas supply as well as visual and audio communication). The diving bell allowed the divers to decompress in comfort for the last four hours of the seven-hour epic dive. The dive went off without incident and as planned until Pim arrived back at –120 meters at which point his dry suit flooded (this was a problem because the water temperature is around 4 to 6 degrees centigrade), he managed to survive and was assisted into the bell at –21 meters by his support diver Remko van de Peppel, at that stage he was very weak and unable to do so on his own. At –100 meters, on the way up Alex started to feel dizzy and had to bail out to open circuit due to vomiting, with the assistance of his support divers and Mario he too was able to reach the safety of the diving bell. Mario’s dive went on without incident and he communicated with the surface from the diving bell, on the condition of his dive buddies. He also assisted them when possible because they were both vomiting frequently while decompressing in the safety of the bell. Upon surfacing Alex was evacuated for further treatment in the Recompression Chamber while Pim whose condition had improved remained under observation. Mario, after a medical examination, required no further attention except for a good night’s sleep. The whole team can be congratulated on doing a very difficult record dive and on recovering from a number of potentially fatal emergencies. I had the pleasure of being a witness to a well-executed dive instead of being one of the divers doing the record, for a change(236m).

Decompression the Basics

2008-07-16T13:32:00.001+02:00

It occurred to me that I take for granted that every divers knows about decompression. What I forget is that most agencies do not teach decompression diving from the get go (CMAS does which is where I started). Most sport agencies rely on NDL, no decompression limit diving to keep their divers safe. It certainly does keep things simple and reduce the entry level barrier to new divers, but as you no doubt know from some of my other blogs, I believe that it is a false economy as divers learn diving without learning the real danger of diving and so end up at 60 meters and wondering why they are bending. So, here are some of the basics behind decompression theory.
Decompression sickness or DCS is the body’s reaction to bubbles. These bubbles can lodge anywhere in your system (brain, spine, lungs, heart, muscles) and tend to be made of either nitrogen or helium (this obviously depends on what you are breathing when you are diving, nitrogen and or helium). The gases that you breathe are transported from your lungs to all areas of your body (tissue) in the blood along with the oxygen you need to survive. The deeper you go, the more ‘thirsty’ your tissues are for these gases, so the faster they absorb them (a process called in-gassing). This absorption process occurs until the amount of gas outside the tissue is exactly the same as inside (as measured by the partial pressure of the gas). When you change depth and ascend the tissue suddenly has more gas than blood and so releases the gas, a process called out gassing. This is the simplest picture I can paint…and so has its own set of inaccuracies, but you get the idea.
Not all tissues have the same reaction to an increase in the amount of gas available. Some are thirstier than others. When a tissue is greedy and absorbs gas fast it is called a fast tissues and when it takes its time to take on board the new gas, it is called a slow tissue. The speed at which tissues absorb gas is used to classify every tissue in the body. To make it easier tissues are further grouped together into compartments that behave in more or less the same way, absorbing and releasing gases at the same rate (Buehlmann created 16 compartments). The compartments are important for decompression programs as the maths then treats all tissues in that compartment as having the same absorption features.
When discussing tissues the phrase tension is often used (tissue tension) which is simply another way of saying the amount of gas (nitrogen or helium) that is absorbed by that tissue (or put yet another way, the gas pressure). The tables ensure that the tension of the gas in the tissue does not drastically exceed the outside tension. When it does.. bubbles result.
The amount of time it takes for a tissue to release (or outgas) its nitrogen or helium is referred to as that tissues half time. This is a standardised unit that measures the amount of time it takes for a tissue to halve its gas tension (halve the amount of gas it has absorbed).
There are a number of different factors that affect whether or not a tissues is fast or slow, these include the degree of blood flow to that tissue (perfusion), the amount of blood vessels within the tissue and so the distribution of the blood to a tissue and the solubility of the tissue (i.e. how easily it absorbs nitrogen and helium.) This means that areas that have a lot of blood vessels (good perfusion) tend to be faster tissues (lungs and abdominal organs). Slower tissues are normally fat and joints. Fat also holds onto nitrogen better (incidentally this is believed to be one of the reasons we are susceptible to narcosis, our neurons are sheathed in fat and fat likes nitrogen).
One common misconception is that as you ascend all your tissues will be outgassing. But not all the tissues find themselves in a situation where the pressure outside is less than the pressure inside… which means that they are in fact still ongassing (the tension of the tissue is less than the ambient pressure rather than greater than). This is more often the case on deeper dives and has been used as an argument AGAINST deep stops ( personally believe the value of the deep stop is to outgas your fast tissues effectively and stop these bubbling and causing problems at shallower levels. My philosophy is to let your slower tissues absorb, I will deal with them when I get to them J , i.e shallower)
A tissue is deemed to be saturated when the tension outside and inside is the same. The tissue is in a state of equilibrium, it neither takes up gas nor does it let it go. Supersaturation is when the tissues have more gas than outside (ambient pressure outside is less than the pressure of the tissue). Bubbles form when based on how high this supersaturation is (i.e. how great the pressure difference) and how long this state remains true. This is termed critical supersaturation.
Another element often referred to in tables is M-values. These are the maximum nitrogen tensions for a tissue after which bubbles form (or the supersaturation point). Fast tissues tolerate higher supersaturation rates than slower tissues and so have higher M-values.
Tables and decompression programs put all this together and use maths to calculate the times you need to stop to allow the tension in your tissues to subside (i.e. gas to be released into your blood, move to your lungs and then be breathed out). Most tables are parallel models in that they assume that all tissues are exposed to the effects of the gas at any one time…as opposed to serial models where each compartment reacts one after the other (which is obviously not true).
Simple right ? J

Why you should be using Deep Stops

2008-07-08T11:20:00.000+02:00

You may already be a fan of deep stops or you may be like a lot of divers, you have heard of them but have been diving successfully for years without them so don’t see why you need to change. Here is some food for thought (my sources for this blog are the NAUI Journal of Underwater Education, Vol 20, Issue 2 and the published journal on the “Effect of Varying Deep Stop Times and Shalo Stop Time on Precordial Bubbles” by Bennett, Marroni, Cronje, Cali-corleo, Leonardi Bonucelli, Balestra, Undersea and Hyperbaric Medicine 2007; 34(6).)
NAUI (as an example which is not meant to imply that other agencies do not already recommend this) had a recommended deep stop of 1 minute at a depth that is half that of the deepest depth reached on the dive. They have now changed that stop from 1 minute to 2 or 3 minutes ( the ideal being 2.5 minutes). This is based on the research by Bennett et al (for us more technically minded divers this ‘deep’ stop should be half the absolute depth and not half the actual depth…and yes, they really mean at least 2.5 minutes…read on)
What does the research say ? Well, it has already been proved that a deep 5 minute stop at 15 m (on a 25 meter dive) in addition to the typical 3 to 5 min shallow stop (6 m) significantly reduces the number of bubbles and fast tissue compartment gas tensions (this research also indicated that the optimal ascent rate from 25 m was 10 m/ minute). This led to a number of agencies introducing the 1 minute ‘deep’ stop. BUT, the new research indicates that 1 minute is too short and actually increases the bubbling rather then decreasing it. Dives with 2.5 minute deeps stops showed the highest bubble reduction. Interestingly the research also found that if you have a deep stop, you could drastically reduce the time you spent shallow without changing the bubbling.
Some underlying theory - most decompression computer algorithms and dive tables are based on the original ideas of Haldane or Hill. Haldane modelled gas uptake and elimination on 5 tissue compartments that were either fast or slow to uptake/ eliminate gas (the compartments are virtual entities into which the various parts of the body are assigned a group, for example, brain tissue and nerves are fast tissues, fat is a slow tissue…I will blog on the basics of decompression next week).
Buelmann increased the number of tissue compartments to 16 / 18 creating an algorithm that is perhaps more accurate and safer as a result. Most models are based on the common premise that as long as none of these compartments become supersaturated beyond a certain critical threshold, decompression sickness (DCS) is avoided. Haldane also (and critically) introduced the concept that it is as safe to come from 6ATA to 3ATA as it is to come from 4ATA to 2ATA, or a 2:1 ratio of absolute depth. This ratio of one half the absolute depth has been modified over the past decades and now ranges from 4 to 1 for fast tissues to less than 2 to 1 for slow tissues. Interestingly though, most tables adopted Hills approach of a linear ascent of 10m/ min with a safety stop at 3 to 5 meters. This meant that the concept of staged decompression at one half the absolute depth was eliminated… and so were the positive effects there-of. In essence this is what Bennett et al are doing, re-introducing a stop at one half your absolute depth. Their research indicates that such a deep stop (for their 25 meter dive) often completely eliminated type 3 and 4 bubbles (bubbles were graded as follows 0 (none), 0.5 (sporadic), 1 (15 bubbles over 1 minute with bubble showers), 2 (30 bubbles), 2.5 (>30 bubbles with showers), 3 (virtually continuous bubbling), 3.5 (continuous bubbling) and 4 (continuous bubbling with continuous showers).
What did they find across their various profiles ?
- After a 2.5 min deep stop, decreasing the shallow stop time from 5 min to 1 min had no significant difference to bubbling. They are do not come out and quite say it, but the evidence seems to indicate that the safety stop at 5 meters can be seriously reduced to as little as 1 minute although they still recommend it for recreational diving to prevent pulmonary barotrauma.
- Without a deep stop increasing the shallow stop time did not give you the same effect as a profile with a deep stop. So basically, without the deep stop you had significant bubbling and nothing you do changes that. This was supported when they increased the shallow stop to 10 minutes (from 5 ) with only a slight reduction in bubbling being reported
- If a deep stop is used, any times less than 2.5 minutes ACTUALLY INCREASES YOUR BUBBLING as compared to not having the deep stop at all. So basically either do not do the deep stop or do it properly spending at least 2.5 minutes, otherwise you are making it worse.

I find this research quite interesting as deep stops have always been part of my profile. In fact, I remember quite clearly asking Dr Cronje what advice he had to prevent decompression and him stating “prevent bubbles from forming” (well his actual answer was do not do the dive J ), which is what this research seems to indicate.

If you want to stop bubbling you have to stop it occurring, which is normally deep in your ascent. Staying shallow is there to remove bubbles that have already formed.

Dives that produce bubbles tend to produce DCS!

Which Dry Suit ?

2008-07-02T13:00:00.008+02:00

Here in South Africa the diving dry suit is more the exception than the norm. Well, for most divers. For those of us diving caves (or Cape Town or long decompression) a dry suit is a must. With the slow adoption of technical diving more and more divers are starting to move towards dry suits. The question is which one ?

For those of you who are reading who are not quite sure what a dry suit is… simply put it is sealed suit that prevents nasty cold water from ever reaching/ touching your skin (well ok, not your hands and your head, although you can get dry gloves and hoods but that is a bit of overkill in Africa). It does this through the use of seals that prevent water from entering the suit at your neck and wrists.

There are many brands of dry suit available to a diver, but only these tend to fall within two main types, a shell or membrane suit or a neoprene suit. Each 'type' has its own set of pro’s and cons, not the least of which is price (indeed price is often the most important factor when selecting a suit).

MEMBRANE DRY SUITS
Shell suits are so called because they are made of a thin, strong and durable material that creates a shell around the diver. This resembles a hard wearing membrane and is made up of layers. For our use the only way to go is a tri-laminate membrane suit as the bi-laminate is just too thin and prone to breaking (a membrane dry suit is worthless if it leaks). As the suit is a thin'ish membrane there is little insularion (unlike a wet suit). The intention is too keep the water out so with a membrane suit inners must be worne to provide warmth. Without the inner (think portable sleeping bag) diving in cold water is akin to standing in a gale with a dry mac on…i.e. cold!
There are a number of advantages to a membrane suit :
- They are cheaper than neoprene (especially crushed neoprene)
- They do not change their thermal insulation and buoyancy properties with depth (neoprene compresses and so becomes less effective)
- They are versatile as you can change your inners (and so your warmth factor), moving from a thin inner (or even just a track suit) to something hectic and more appropriate for arctic conditions.
They do however have disadvantages:
- They are not as flexible as their neoprene cousins, so if you are dressed up for warmth reaching fins can be a problem
- They have little to no thermal insulation properties so if your suit floods, you stand the chance of freezing unless you have some hectic inners or a heating system (they do exist)

NEOPRENE DRY SUITS

The neoprene counterpart comes in two varieties, normal neoprene and of course the deluxe and ultimate... crushed neoprene. The big difference with a neoprene dry suit is that you tend to use them without inners (unless you are using crushed neoprene of which the DUI is the only choice).
Advantages of neoprene:
- They have in built thermal insulation like a wet suit so if you have a loose fitting one (not normally the case, they normally fit tight like a wet suit) you can add warm inners and so create the ultimate suit for long, cold stays
- Because they are neoprene, if you flood your suit you stand a better chance of heating the water up and surviving
- They are more flexible than a membrane with more give
Disadvantages are:
- Unfortunately unless you are diving crushed neoprene, you lose a good part of you insulation properties at depth thanks to compression and you end up with buoyancy issues
- Price! Crushed neoprene suits will make you weep and even normal neoprene is more expensive than a membrane

So which to choose ? I did my world record using a Scubapro membrane suit. Nuno Gomes prefers neoprene because of the thermal insulating properties. I have now moved to a DUI crushed neoprene but the jury is still out. There was nothing wrong with my membrane and the only reason I moved to neoprene was because my next dive will be over 6 hours and I need extra warmth (read on for the paragraph on pee valves). Most of the divers we talk to make their choice based on price, which means membrane (especially if they need a custom fit).
Once you have chosen between membrane or neoprene you still have to choose from selections like;

telescopic torso (a must as it gives you manoeuvrability, flexibility and comfort),
where the dump valve goes shoulder or cuff (shoulder is better as it is out of the way and high up on the suit, on a cuff dump you have to spend your ascent with your hand above your ear….kinda inconvenient)
and whether or not you want extra thigh pockets (yes, you do, they are damn handy)

Suits also come with back entry or shoulder/ front entry. To be honest, I still need help on the self donning shoulder entry suit but only with that last centimetre. Having said that, the self donning is still way easier to get into and out of than the standard and more common back entry which requires either a second person or some interesting antics as you try and ‘catch’ the zip tag and then pull it closed (or open) using a convenient protrusion (think cat scratching its back)

When it comes to a brand you have a wide choice, especially with the internet. Our recommendations are Otter or Scubapro (naturally) as these fit within our target price range (you do not want to know how much a DUI is these days). We find that we sell more Otter's simply because you can get a custom fit at a really reasonable price (and to my eternal regret, Scubapro does not make custom fit suits). Why is custom fit so important ? Well most divers actually battle to fit into the standard off the shelf cuts, especially if you are female and buying a male cut (which is often the case). Custom fit also means you do not have to spend your life with a size 8 or 10 boot when you feet are a size 6 (based on the off the shelf suit you had to choose to get your length and girth to fit).

Another question that is hotly debated is when to purchase a dry suit ? Normally divers leave the dry suit to last, well after they have bought their Liquivisions or VR3's. Which I find odd. You can always (and normally do) plan your dive on paper so a helium computer is a luxury BUT you can not easily unfreeze yourself doing those 2 to 4 hour dives in cave cold water. From a pure risk management view point maintaining your body temperature should be one of your primary and critical factors that you are managing. Being cold is just way more of a risk than having a snazzy helium computer that means you can cut corners and not plan on paper before a dive. My advice is always to get the suit before the computer (they cost more or less the same).

The final topic that does need to be discussed (and one that I am not going to blog about, I will leave that to Gerhard) is that of pee valves. This is a conversation that I really do not want to know more about and is exclusively an option for the male dry suit diver and yes, I am jealous. When I do a deep dive I have to wear incontinent nappies which last like twenty minutes after which I am wet and cold . The guys fit their condom catheters and spend a blissful 4 hours warm and more importantly dry.

Would I ever go back to diving wet ? No way! I have only ever been too warm in a dry suit once and compared to being almost permanently cold and unable to warm up after repetitive dives I think the warmth of kitting up in mid summer is a small price to pay. Admitedly sea dives take some getting used to these days as it is harder to get back into the boat because I have a power inflator on my chest that catches me as I try and get in but then again, sea dives are not really on my agenda much so I guess I can live with the inconvenience. If you are a technical diver my only question to you is, why are you not diving dry yet ?

Being a Good Buddy

2008-06-25T12:18:00.000+02:00

As is often the case, inspiration for a blog post comes from listening to the stories of other divers.In t The world of diving I came from there was a mixture of newbies with older, more experienced divers. This mix meant that individuals did not have to learn the hard way with the older divers adding a level of caution and responsibility to the group as a whole. These days active technical dive groups are few and far between and where they do exist they tend to comprise almost exclusively newbies. This means that the normal self regulating buddy influence is not as strong as it needs to be. Each member of the group is at the same level so there is a tendency for individuals to not take seriously the feedback or concerns of the rest of the group. Likewise iindividuals in the group are still finding their confidence so do not have a solid set of standards that they are prepared to enforce (like refusing to dive with a buddy who is drinking, or refusing to dive with a buddy who is piggy backing on your computers and has not done his own planning).
This sense of uncertainty extends to situations where a buddy pushes his limits to the point of being physically affected. He gets out the water looking a tad pale and then starts to throw up (discretely). What do you do ? There is a good chance that the buddy is not going to take kindly to being driven to the closest hospital just because he is throwing up. Do you leave him ? After all he is a grown up! Where does individual responsibility end ? Where do you draw your own personal line ?
I understand the dilemma having had a similar experience with a very close friend. He was doing support at 100 meters when i was doing one of my deep build ups (140 m if I remember correctly). By the time I was out the water he was already back at camp with a migraine and throwing up.
This raised alarm bells for me. Yes, he was prone to migraines, but one of the fundamental guidelines for making decisions on a diving trip is that all physical symptoms are first attributed to diving and a possible bend, then to normal day to day niggles. No-one wants to make something big out of something small, so our tendency as individuals is to mind our own business and do nothing. By 6 in the evening my buddy was worse and still throwing up. He was also belligerent and refusing help. We phoned Dan!
They recommended we take him to the closest hospital. We were loathe to do that, after all it was probably just a migraine and hospital sounded like over kill. We would also have to force our friend to go. By 8pm the situation had not changed and as a group we realized that we would rather look foolish on Sunday then have a good friend seriously and permanently injured. We dragged him kicking and screaming to the hospital. They were also unsure but sent him off to the chamber just I case and a good thing to, because it took a chamber treatment to recover his memory and get him better. We are still not sure what exactly happened. It was probably a cerebral bend which meant if we had done nothing our friend would have been permanently impaired.
What did I learn from this ? Two things, firstly you look more foolish when you do not react as if it is serious and secondly, I need to be able to live with myself and that I do not want to live with the guilt of having done nothing and seeing some-one die or become crippled. Most of the things I regret in diving involve not speaking up. You may not change anything by speaking up, but you at least offer the individual the opportunity to make a different choice.
This means that I am vocal about my expectations of a buddy because it is not only about them, I have to live with what happens as well. We agree before hand how we expect each other to behave. I expect my buddies to tell me if they are concerned about decisions I am or am not making. I expect them to keep an eye on me after a dive because I know that if I am not feeling well I probably will not mention anything and it will probably take someone making something of it before I go to hospital. I expect my buddy to have high standards and to care about his life and mine!
So next time you are on a trip and you see yoru buddy acting in a way that will endanger his life or your own, speak up! If you are still uncomfortable do not do the dive (or at least not with him). Keep an eye on your buddy after a dive and check up on him. If he seems to be ill call him on it. Phone DAN and ask for their advice.
Remember, life is too short for regrets and trust me, when something goes wrong you will regret doing nothing and ‘going along’ to keep the peace. I would rather have a buddy who is cross with me, than a dead or impaired one.

Trusting an 'Experienced' Diver

2008-06-11T13:55:00.001+02:00

How do you Define ‘Experienced ‘ ?
I was pondering the concept of an ‘experienced’ technical diver (or any diver for that matter.

The reason why I am curious is because associated with the word experienced comes a whole host of privileges. I routinely see or hear about so-called experienced divers who take it upon themselves to ‘break’ their agencies rules (sorry, the politically correct term is ‘make exceptions’). It seems that along with the label ‘experienced’ comes immunity (and in some cases an almost God like power). The really disturbing aspect is when (as apparently an experienced diver) I get asked by newbie technical divers to ‘take them’ outside of their training and experience. The implication is that my experience will keep them safe…which disturbs me greatly. Nothing in my experience has equipped me to be soley responsible for some-one else’s life.

What do we as a community mean by this rather vague yet powerful word, ‘experienced’ ?
If one looks at the different agencies they all have standards in place to define the level of experience a diver must have in order to get onto a course or to complete a course. Depending on the agency this is defined as a number of dives or a number of hours in the water (there are also a set of skills that need to be practiced a certain number of times to complete a course). But once you have finished with a course, how can you as a diver tell if the person you are about to dive with is really competent and experienced ? Or out another way, how do you know if you can trust this dude with your life ?

Often step one is to find out what agency they got their certification from the theory being that some agencies offer better training than others (which is mostly not the case these days).
Step two is to take a look at who his (sorry ladies, it is invariably a he) instructor was. There is a common belief that the quality of a diver is based more on the instructor than the agency, the theory going that a good instructor will make up for his agency’s ‘bad’ points and produce a diver that is more competent. I would like to believe that there is some truth to this belief and that even within an agency one can see a difference between competence in students that goes beyond the students individual ability.
But both of these mechanisms are qualitative. Just because a diver has had the best instructor from a highly credited agency with strict standards (that are actually enforced) does not mean that a diver is going to be competent and capable. So what next ?
Step three is normally to get an understanding of how many dives the dude has. Which is all well and good, but what we forget to ask is over how many years and when last he dived. What we also forget to ask is where those dives were been obtained ? An example perhaps…

Meet Jo Blogs. He is a certified Normoxic Diver with 250 dives to his name. Sounds good right ? What he forgot to tell you is that he started diving nine months ago and the first 150 of those dives were obtained thanks to a number of hectic weekends at Bass Lake. Now meet Bob Smith, he has 120 dives, has been diving almost two years and has less than 30 dives in Bass lake. Of his 120 dives less than 30 are shallower than20 meters or shorter than 30 minutes long. Which one would you prefer to dive with ?

Or what about Jim Green who has been diving for ten years, has 300 dives to his name but has not done anything other than the odd sea dive over the last 3 years and now wants to do a 60 meter dive with you ? Then there is Phil Black who has been diving for 5 years, has over 400 dives (most of which are deeper than 30 meters) but has bent himself stukkend (broken for the international readers) on several occasions (you later found out that he was not breaking the ‘rules’, but would it make a difference ? )?

Tricky isn’t it ? Most of us are fairly careful about who we end up underwater with. We surreptitiously institute ‘trial’ dives that allow us to gauge the person’s skills for ourselves, but what happens when it is not a buddy you are trying to gauge but an instructor ? Most instructors pride themselves on their reputations and their abilities (real or perceived) and most are not open to the concept of you the student trying them out.

We assume instructor competence and experience because of the pieces of paper they have - their certificates. These certificates carry with them some important assumptions. Each one means that the instructor has passed that agencies prerequisites. On paper these pre-requisites and standards are impressive. Instructors are required to have a certain number of dives, have assisted on courses, have practiced lectures, have demonstrated all the skills and have ‘bought into’ passing on the agencies standards and methods .

What we do not know is that agencies love to do paper cross over’s which do not require you to physically fulfill the course requirements from either a practical or theoretical perspective. Even more worrying is the concept of instructor and instructor trainer discretion, which means that once qualified an individual may effectively ignore his agencies rules because in his opinion the student is competent and capable. The student does not necessarily need to demonstrate this or any of the skills required for his certificate. In the worst case scenario instructors have been blessed with certification in a matter of hours.

All of which means that the pieces of paper we rely on so much to grade the divers around us are pretty meaningless.

So how do we define experienced ? My personal perspective is that the only way to gauge a diver’s ability is to dive with him and spend time with him, both above and below water. This is a much safer (and accurate) approach to determining the safety and reliability of a diver than either his logbook or his certificates can ever be.

So next time you hear the word ‘experienced’ look a bit deeper… and take the time to judge for yourself. After all, it could be your life on the line!

The New Hammer CCR

2008-06-03T09:46:00.006+02:00

Well, some of you know that I decided to sell my inspiration new vision and go for the new Hammer CCR! Gerhard (my partner in crime....err diving:) ) is in the States at the moment fetching it and getting the training, so I thought I would post his comments after meeting Kevin Juergensen and personally getting a tour and picking up my new baby.

FROM GERHARD :)
OK! This is the best piece of engineering I have seen so far. I had a nice meeting with Kevin Juergensen. Did you know the guy has mk15.5's coming out of his ear - (try 4 NEW ones still with labels and paperwork on them and yes, they are for sale at least 13 000 US with complete hammerheads etc. But in their boxes....too cool). I saw mk 16's for Carleton technologies for the military, anti magnetic with the newest displays etc, was not allowed to photograph it but Kevin showed me some amazing stuff. Those crazy compound plastic and carbon cylinders that weighs noting and rated 300 bar etc... he has infrared in the handsets and other things I am not allowed to mention. What i can mention is the fact that the new hammer handset will be as flat as the vision ones with ability to rotate the display 90 degrees at a time and all sorts of goodies (the wire will become ribbon type encased cable etc...).

One of the pluses of visiting in person (other than getting to drool over Kevin's workshop) is the that I will get a course on doing repairs to the Hammer handsets, so I can replace circuit boards, pressure transducers , lenses , displays etc without having to post the hammers back to the States (costs a small fortune). How cool is that? All approved by hammerhead, warranty NOT void....

Now for engineering, this is the BEST I have ever seen.(Kevin is a perfectionist - as he explained it was all out or bust,the best or nothing) Everything is made in Czechoslovakia and it is PERFECT - all hand machined, every part fits like a glove, solid delrin, high flow a.d.v. (similar to the meg/cis), anodized aluminum scrubber canister, axial/radial scrubber (takes 3.5kg sorb) AND I saw the first extend air cartridge that kevin had made, thing will give you easily 12+ hours! HUGE, looks like a little cylinder. I am attaching photos ( low resolution) for you of the the canister , locking lid, lungs, GOLEM Box (included). For those people in South Africa we have negotiated a special deal - the units will ship with the storm case AND cylinders for the same price and of course we get metalsub connectors for the cylinders, c+ handsets, a.d.v., flow stop, big canister (you can get a half one for baby dives if you want) etc etc.
I have to say I was a bit worried about the thing until I got it. Bloody hell, my inspo is up for free at this point. Its got nice manifolds, they use apex 1st stages. I have been promised 4 week turn around on the machines, 2-3 weeks on an inspo hammer head.

The worst was leaving there as I did not want to bugger off - the amount of spares that guys has! Cis lunar , mk15/15.5/16, his 1st circuit boards...was just crazy, a machine that looks like darth vader, an 800 liter a minute compressor... o yes, and they just landed a 15Milion dollar contract for the military....

A complete hammer is US $ 10 700 excl deco on secondary, and 3450 for an Inspo Hammer replacement excl deco. Also (much against kevins will, but me being a persistent) I can also now do a proper liquid fill off the handsets...

O yes, did I mention my machine is up for sale... 5 bucks :)

Will post pics on http://www.tekdiver.co.za/ (and no, Verna's new hammer ccr is not for sale)

Which Rebreather ?

2008-05-26T12:48:00.012+02:00

These days more and more divers are moving onto machines (or rebreathers). The advantages are many (longer dive times, cheaper mixed gases, feeling better after the dive). The only real disadvantage lies in the price (at least R40k up front) and of course the fact that you have to get spend time getting experience on your machine before you can get back to doing the dives you where doing on open circuit.
The good news is that gone are the days where the only machine you could choose was the Inspiration. These days South Africa has access to pretty much any machine, from the Scuba Pro Submatix to the new Hammer CCR.

Below is a short list of the readily available machines in South Africa. The prices quoted are in Dollars so that you have an unbiased comparison (all the prices come from dive rite express).

1) SCUBAPRO SUBMATIX
This comes standard as a semi-closed machine and can be converted to a full closed circuit, although the cost of the conversion makes it more cost effective to go straight to a fully closed machine. Price $7,000

2) Megalodon
This is a fully closed machine and available in a number of configurations, so you can basically put together a machine to match your requirements. Stands up well to the better known Inspiration (which comes in only one format).
Second hand units are not available currently in South Africa. Price : $8000

3) New Hammer CCR
This is an exciting unit (I may be biased as I sold my inspiration new vision for one). The unit is designed for deep exploration and comes with the famous hammer head and controller (which most deep divers purchase and fit onto their inspirations or megs). It also has a radial scrubber which is yet another plus for depth and duration. Another feature worth mentioning is the pre scrubber oxygen injection (the oxygen mixes before it is measured). it comes standard with an ADV (the magody that injects your diluent without you having to press a button...a must). Oh and it has been dived successfully in the 200 meter range. Training will be available from June 2008 from Gerhard du Preez of Liquid Edge Diving. Price : $10,500

4) Inpiration (Classic, New Vision)
The best known rebreather (especially in South Africa). A big plus for us here is that units can be found second hand from around R35k (for the classic, add at least 10k for a new vision or evolution), which makes Inspiration the more affordable alternative.

One of the down sides of the Inspiration is that it comes in only one configuration and the cost does not include items like an ADV (which really is a necessity these days). The new vision electronics includes decompression software which gives you a second computer although the verdict is still out as to whether or not it is better to have a classic and two Liquivisions (is certainly cheaper than a new vision and a Liquivision computer). From a depth perspective it handles well up to 150/ 180 meters after which the electronics need to be upgraded to the Hammer Head (you are looking at another $3,000) Price : $10,000

So...when you going to take the plunge and go silent ? You know you want to :)

How Many Agencies can you Name ?

2008-05-21T12:40:00.017+02:00

I thought to myself that it might be fun to see what info you can find on the net about technical diving agencies. As South African techies we are accustomed to having limited (if any) choice when it comes to a technical agencies with only two of the ‘international’ agencies having made it to our shores, TDI and IANTD. This is not the situation over the pond where there are a number of agencies to choose from, some with as impressive (if not more so) pedigrees as our established brands.

The question is, how many do you know about ? The agencies are listed by age, oldest first.

ANDI (1988) (American Nitrox Divers International www.andihq.com). Started in 1988 by Rutkowski and Ed Betts. Interestingly ANDI and IANTD share a founding father (and agency) namely Dick Rutkowski and IAND (International Association of Nitrox Divers, which was began in 1985). Rutkowski sold IAND to Tom Mount (who was an ANDI Instructor Trainer) in order to commit fulltime to ANDI. As an agency, ANDI's courses cover nitrox (or safe air as they term it), trimix and rebreathers (but not cave diving). Another interesting feature of ANDI is that they refuse to provide paper cross over’s of instructors (their site is definitely worth a read). Gerhard is off to the States in a week or so to get his instructor rating on the new Hammer CCR with Joe Radomski (the technical head of ANDI) so I will hopefully be able to report back a bit more on other side of technical diving across the pond.
IANTD (1992) (www.iantd.com) or in its longer version, the International Association of Nitrox and Technical divers. Evolving from Dick Rutkowski and IAND, IANTD these days is synonomous with Tom Mount who bought it out in 1992 and created the IANTD we know today. Their courses cover the full range of technical i.e, trimix, caves and rebreathers. The international site provides a look up of instructors and so allows you to find the instructor nearest to you (it is the only site I found that allowed you to do that).
TDI (1993) (www.tdisdi.com). Technical Diving International was founded in 1993 by Bret Gilliam and Mitch Skaggs and is one of the largest technical agencies out there (and I believe the first to arrive in South Africa). The TDI course structure offers a suite of building blocks supplemented by good manuals (I particularly enjoyed the rebreather manual). Their courses cover the full range of technical i.e, trimix, caves and rebreathers.
NAUI (1997). Well known as a sport agency NAUI have had a technical division since 1997. Founded by Timothy O’Leary the NAUI technical board is sprinkled with names like Bruce Wienke and Bill Hamilton. There program covers all aspects of technical diving (and yes, it is available in South Africa – soon you to be on www.tekdiver.co.za). Personal experience with NAUI technical here in South Africa indicates that it promises good things, such as no paper cross over’s for instructors (visible and proactive maintainance of standards is something I am passionate about...which means I am furiously practicing long forgotten underwater snorkel skills for my impending cross over), high quality manuals and good customer service. Their courses cover the full range of technical i.e, trimix, caves and rebreathers.
ITDA (1997) (www.itdahq.com). Otherwise known as the International Technical Diving Association. I have to admit that I only found out about this agency by doing a web search. It is British based agency established by the late by Rob Palmer in 1997 and appears to be very popular in the UK and Europe.
GUE (1998) (www.gue.com). Established formally in 1998, Global Underwater Divers have become iconic in technical diving in part due to the reputation their founders established with their branded methodology, DIR (Doing it Right). These days Jarod Jablonski promotes DIR training and some hectic exploration (their favourite site is WKPP which has some impressive dives). Unfortunately there are no certified GUE instructors here in South Africa (at least not that I am aware of) although there are some intrepid divers who have done a course or two on their own bat.

In addition there are two notable cave diving only agencies (once again based in the States).

NSS-CDS (www.nsscds.com)which is the cave diving section of the National Speleological Society
NACD (www.safecavediving.com). Otherwise known as the national association for cave diving. This is an interesting site (and organisation). Did you know that they have an award system available to their divers (the Wakulla Award) based on the number of successful and safe hours (or logged dives) in a cave ?

So, how many did you get ?

Technical Agencies, Branding & Competition

2008-05-14T10:24:00.011+02:00

I was sitting writing about wings and bladders and harnesses and back plates and found my thoughts wandering in a totally different direction. Probably thanks to lunch on Sunday when we had old friends over and started to talk about the good old days. Diving in South Africa started out very much club based (like BSAC in the UK here called SAUU which is now CMAS). When I started way back in 1989 you could count the number of diving schools on one hand…and they were NAUI (no-one had heard of PADI). These days NAUI has taken a back seat to PADI and CMAS/ SAUU has practically disappeared. Sport divers are spoilt for choice and a popular discussion point is how ‘fly by night’ sport schools spring up under-cutting established schools with un-sustainable pricing, ‘steal’ students, provide shoddy training and then go bankrupt six months later. Running a dive school is a tough business and highly competitive. To make matters worse, South Africa tends to be highly price sensitive which means that quality is not often a differentiator when divers pick an instructor or school.
So how does the technical diving market compare ? In sport diving you have an abundance of choice when it comes to agencies, schools and instructors. At last count you could choose from PADI, NAUI, CMAS, SSI/ TDI and recently IANTD. Basically, no matter where you live you should find at least one instructor or school who can teach you how to dive. In technical diving live is not quite so rosy. Back in 1989 the international agencies like IANTD and TDI were not well established. You had to rely on SAUU/ CMAS for technical qualifications and as most instructors were not fulltime, courses were few and far between. The arrival of full time, international agencies seemed to promise change, at the very least it should make technical diving more accessible (like the revolution that was happening within sport diving) .
TDI was the first of the ‘big’ names to arrive on our shores, followed by IANTD. However it soon became clear that the principles of expansion and market penetration that were being applied by agencies like PADI and NAUI were not being applied by TDI and IANTD. Where sport diving grew through the active training and dispersement of instructors (creating a plethora of choice for new divers) technical diving remained closely associate with individuals (for TDI read Steve Minnie and these days Dave Kitchen, for IANTD read Mike Fowler and Don Shirley). Instead of the spread of instructors and technically affiliated or inclined schools that one would expect with the arrival (finally) of South African international franchisees, the landscape looked (and still does) pretty much as it did in 1989 – with agencies being synonymous with the founding instructor and branding seeming to go no further than promoting the franchisee’s reputation and designed to acquire them students rather than promote all agency instructors.
The technical market it seems, is be well and truly ‘locked down’ and controlled by a couple of individuals.
Which made me wonder why the sport and technical diving are so different when it comes to the business and promotion there-of ?After all it is divers we are talking about and technical diving is a natural extension of sport diving which has a huge base.

In sport diving you are inundated with adverts for agencies like PADI and if you phone the agency they tend to promote the closest school to you. In technical diving the opposite holds true. Divers interested in technical diving who do respond to what little advertising there is and phone up a specific agencies are never told about their closest instructor but instead are actively sold the individual behind the brand. Instead of creating a pervasive and accessible technical brand we are left with agencies that appear to be little more than one man shops. Which hardly creates incentive for existing or potential technical instructors. Surely ‘brand’ or agency advertising should promote equally all instructors of that brand and not just one individual ?
What does this mean for technical diving ? Well, firstly the franchisee’s are responsible for training new instructors and so ‘spreading the word’ or getting instructors out there in every major dive centre in South Africa. This makes business sense because the more instructors you have the more students and therefore the more income in a month through package sales and gear (especially if you are also an active gear distributor to that instructor base). Yet even after over ten years when one looks at full time instructors there are only two active full cave instructors in South Africa Don Shirley (the IANTD franchisee) and Gerhard du Preez (co-owner of Liquid Edge Diving). A similar situation exists when you look at Trimix or Rebreather diving where the choice is slightly extended with the introduction of TDI representation (Dave Kitchen, the local franchisee).

This impact of limited choice and penetration on the technical diving community is extensive. With no competition, prices are controlled by individuals. Instead of the pricing policy that is working out there in the sport community where the principle of ‘a small piece of a large pie’ applies (or put another way, you can afford to charge less because you have more divers coming through the door) the technical community appears to operate from a principle of ‘a large slice of a small pie’. As the pie is small prices are high and the effect of high prices is that access is restricted. You end up with a self fulfilling prophecy – with a few full time technical schools competing for a small number of divers and as the numbers are small everyone has to charge high prices. I have to question the base assumption that there are few technical diver wannabe’s out there, not when the sport base is so large.
PADI is not the only success story when it comes to brand penetration, ScubaPro has done a very good job in turn. Here a specific brand has managed to get penetration into the highly competitive equipment market by promoting and actively focusing on their dealers and dealer network. They want people to be selling their product. They want it to be easy for a diver to find and buy their product and as a result Scubapro is one of the top diving gear brands (if not the top) in the industry.
Where am I going with this ? Well Liquid Edge (the diving company I co-own with Gerhard du Preez and the only technically focused full time dive school outside of the franchisees) recently had the opportunity of taking on board NAUI Technical (yes, NAUI offers a full range of technical courses and is one of the only sport branded agencies who does so. No-one was more surprised than I). It was a tough call because based on the fact that we are operating in an artificially created small and ‘elite’ market and we had to ask the question, does South Africa need yet another technical agency ? After all, there is nothing wrong with the standards laid down by TDI or IANTD. After investigating NAUI’s standards and courses I for one felt an immediate affinity. Their instructor cross over was an eye opener with absolutely no slack or concessions given even though Gerhard is a full time technical instructor for both TDI and IANTD. He had to do all the skills, sit in on all the lectures and do all the course work which was certainly not what we were expecting. They also require two pairs of eyes to pass off students, which means you have inbuilt quality control that is not just preached, but practiced (something I have not yet experienced or seen in technical diving). The real sweetner though was the fact that NAUI is looking to actively cultivate technical instructors and get them out there where you as a diver can find them (you try find a technical instructor in Cape Town or Durban, never mind Bloemfontein). All of which can only be good for technical diving. I firmly believe that technical divers should be able to choose from a range of agencies and a range of instructors.

I for one would like to see the day when divers are spoilt for choice when it comes to choosing a technical instructor. When you have a choice you can expand the criteria by which you make your decision, adding aspects like pro-active and visible standards management, quality of training material and C-cards not to mention service and pricing. There is one other big reason I would like technical diving to become more accessible to more divers. It gives you a new toolset that allows you to extend your limits and go and explore new places and I would like all divers to have that opportunity ! I certainly do not regret the journey that technical diving took me on. Oh, and it would mean more support divers (or is that people to braai with J ).

Cave Skills Continued - Lighting vs Helmets

2008-05-07T14:17:00.000+02:00

Sheck Exley was one of the first divers to identify a set of common cave skills that related directly to deaths or incidents underwater. One of these was the fact that cave divers should carry with them appropriate lighting. It sounds rather obvious, caves are dark… in order to see you require light. Strangely though his use of lights was a back up system (you used the line to get out, not lights) - lights helped you get out faster using less gas and in some instances with less cuts and bruises from unexpected obstacles.
The modern school of thought is that every cave diver has at least three lights, a primary and two back up lights. As far as basic characteristics goes, lights need to be:
- As bright as possible, an easy task these days.
- Uniform across a dive team, i.e all divers should have lights of approximately the same brightness. This concept is based on human physiology, so long as there is no bright light to destroy the natural adaptation, our eyes are capable of adapting to dim light conditions.
- As small as possible and neutrally buoyant (large lights get snagged on risk in narrow areas and are hard to manoeuvre with in strong currents)
- Dependable (water and pressure proof), easy to repair and maintain and with as small a failure rate as possible.
Finally, each light should also last as long as the planned dive (which is not as obvious as it sounds).
When it came to configuration of lights Sheck was not so talkative. Modern school of thought sees a primary canister light neatly stowed on the waist belt with two secondary lights stowed on the shoulder straps. Helmets make no appearance what so ever. For those of you who are not familiar with all the gadgets that come with technical diving, canister type lights have a battery in a canister (hence the name) that is connected to a light head via a umbilical. The diver holds the light head with his hand using a Goodman handle which basically attaches the light head to the top of the hand.
Using the light is not intuitive (or at least I did not find it so). In order to see you have to point your hand in the direction he is looking… something I found intensely annoying when I first moved over to this configuration - my hand would be doing something which would mean my light would be facing any direction but the one I wanted to swim in or look in.
Older divers such as myself did not grow up in a world of canister lights that provided liquid sunlight at the flick of a switch. We used normal hand held style torches and in order to accommodate high failure rates as well as light up the cave, we had to use lots of them. Which led to the interesting problem of how to practically transport them all…you only have two hands. Enter the helmet! This was the perfect solution as it could carry four, maybe six lights without using up valuable hand space. As any technical diver will tell you, diving can have quite a significant task load and not having to worry about lighting up what you are doing or where you are going makes life a whole lot simpler.
The down side of the helmet is that it can be very buddy unfriendly. It takes time and practice to not blind your buddy when casually looking in his general direction. This fact has been used to chastise most helmet divers and promote the use of the simpler canister torch with two stowed back up lights.
But, technology comes to the rescue. Just as the need to carry spans of torches has fallen away thanks to the evolution of canister lights, so has the need to have a large, bulky and heavy helmet in order to carry one (heavy) torch just to light up your immediate area. These days lights come small (the mini Q40 springs to mind, Sartek has some stunning baby lights as well). These can be easily mounted on a mask strap and because they are not killer bright, do not blind surrounding divers.
I will miss the sight of divers plunging into the darkness, small white haloes of light replacing blocking out facial recognition and whilst there are some dives (deep, task loading, where a helmet does have a place, for the rest of us, the era of the helmet is well over.
Long live liquid sunlight and canister lights!

Update on Fatally Flawed (My Memoir)

2008-05-06T17:12:00.000+02:00

Saturday 19th of April saw the official launch of my book, Fatally Flawed (The Quest to be Deepest) and it is turning out to be an interesting journey! For those of you who have heard the rumours - the book is still in print and has not been 'pulled'. The word controversial is however starting to apply.

Reactions have been varied. For me it has been a revelation. Truth it seems is very subjective, reality even more so! Which makes me wonder how real our individual realities are. If every person on a dive experiences something different and in fact sees that dive differently whose version of the 'truth' is real ? How many of us Dare to Be ?

When Computers Crash

2008-05-06T17:07:00.000+02:00

Well, I have been offline (as you no doubt have noticed) thanks to a computer crash. I am however back.... and can only say I hope dive computers do not run on Microsoft..can you just imagine the joy of being at 60 meters for your computer to blue screen on you ?

Cave Skills Part 3 - Gas Management (Part 2)

2008-04-15T15:22:00.003+02:00

The basics of gas management dictate that you always have sufficient gas in order to exit the cave and complete your required decompression. It sounds a whole lot simpler than it actually is because there is no iron clad rule that says this is sufficient gas. As a community we agree that you should be carrying at least two thirds more gas than you require to get in (i.e. your deepest point or the end of your planned bottom time) but that does not always provide enough gas and certainly does not do the job when you are looking at a complex plan that uses multiple gases. My previous blog addressed the concepts that I use to calculate sufficient gas and as you can see, even in that there are some ‘loose’ areas, areas where I working on assumptions and so increasing my risk to the point where getting out is more luck than planning. However, I understand when I am entering this zone and I have options to avoid it. Accepting additional, non-controllable risk is an option I give myself. It is a choice.

There are other choices to make when planning your gas. Aside from the thorny issue of how much is enough, there is the strategy you use to supply that gas. Most gas management strategies view the dive team as a single entity and distribute the bail out gas amongst the team. They assume that an incident will affect one person only, leaving at least one (if not two) additional team members to assist. They also assume that the team will always be together so the gas is always available when needed. These are all assumptions that I am personally very uncomfortable with because I am having to place my life in the hands of another person. I guess it boils down to the fact that I simply do not believe that your buddy is someone you can trust your life to. Things happen on dives.

What if the team splits up and you now do not have all the planned bail out gas ? What if two divers are in trouble ? What if the divers are unable to get their stress under control and as a result that well laid plan is completely irrelevant and you are now in a situation where it does not matter how little you are breathing, your buddy is munching gas at a rate of knots ?

It is not that I am saying that I dive with unreliable people, I do not! But there are just some responsibilities you do not hand to people you love and respect. I do not want the people I dive with to have to live with the niggling doubt that they some how were responsible for my death. If for reasons beyond their control they were not where they were supposed to be and as a result I did not have the extra gas I planned on and I die, well that is not a burden I want to give people I care about. Things happen on dives. Things that are beyond an individual’s control. The only life I am responsible for underwater is my own. If I see someone in trouble I will still attempt to help, but I am not sure I would be willing to place my life on the line. Maybe I will, maybe I won’t. I don’t know, not until I am there. Is that uncertainty something you want to trust your life to ?

As a result, I believe that dive teams should plan dives as if each member of the team is diving solo. No diver should count on using his buddies gas to get out in an emergency (it is there, but not part of the plan). This is far safer and far more reliable an option, even if it does require more planning. Some may argue that it adds an element of complexity to the dive, after all if you have a three member team doing a deep penetration you now have to have three times the kit all of which has to be staged in the same place, creating clutter and possible problems when divers all try and get to their gas at the same time. My answer is perhaps, but those are predictable and therefore solve’able problems. You can change the process - each diver can stage in a slightly different place to avoid congestion. The worst thing that can happen is that one or two of the divers are late on their plan…alive but late. Not having the gas because your buddy never made it is a situation that is unsolve’able, especially underwater.

There are plenty of decisions like this in the world of extreme exploration and it is easy to get bogged down in which way is right and which wrong. There is no right and wrong way, only different sets of risks, different sets of probabilities. As a diver you need to understand all sids of the story and choose what fits you. If in doubt, there is one rule that makes decisions simple, find out which option will definitely kill you if you encounter it, and choose the other option, If you don’t’ like the other option, you should be choosing not to do the dive.

Cave Skills Part 3 : Gas Planning (part 1)

2008-04-09T14:20:00.002+02:00

Easter 2004 and I found myself in the one situation no cave diver wants to be in, stuck at 152 meters, 10 minutes away from my nearest support diver and 15 minutes away from my staged gas. This was not supposed to happen! I was attempting to reach 160 meters in a narrow incline (well actually decline) shaft at Badgat. It had taken a 3 minute swim at 100 meters to get to the entrance and whilst narrow, the last descent was relatively simple – a quick in and out. My planning was (as always) a balance of practicality (there are only so many cylinders you can beg borrow or steal) and conservatism (I want as much air as possible to breathe). The problem was that all my planning had revolved around losing gas and then being able to head back to the safety of a support diver or staged gas. I had not planned to be trapped at depth having to rely only on what I had brought along to get me through. No wonder Sheck Exley had gas planning as his number two factor for surviving in a cave.
Sheck’s rule for gas management is most commonly referred to as the rule of thirds. Simply put, you use a third of your gas to get in, reserving a third to get back out and leaving a third for emergencies/ your buddy. The assumption is that you should use the same amount of gas (if not less) to get out and that if there is a problem, you will use gas at the same rate as your entry. These assumptions do not hold true all the time (which is always the problem with assumption) but as a guideline it is solid and gets divers thinking along the right lines – plan for the unknown.Do I use the thirds rule ? Yes, on every day, conventional dives (and there lies the risk… what dives conform to that definition ). But on a deep or extreme dive I use critical pressures to manage my gas requirements. For those of you who are unsure, the critical pressure is the number on your pressure gauge at which you must turn around. Put another way, the critical pressure tells you when you have reached that point where the gas that is left will get back to the surface and includes your ascent rate, travel time and any decompression obligation. It also includes that third reserve for emergencies. If you are doing a dive that uses staged gas to get you out, your critical pressure is that pressure that will get you to your next set of staged gases a opposed to the surface.Actually, as I write I realize that gas management is not as simple as using a flat rule of thirds. It is a complex three dimensional problem that includes parameters like the number of gases, how deep you can stage, what your decompression is, how fast you are going to ascend…. Let me explain.
My dive was to 221 meters. Now I know I can not carry my entire gas supply with me (well I could, but what is the point if I am in a cave and can stage), so I will carry enough gas to get me from a specific point (35 meters) to 221 meters and then back to a different point (my first decompression point and deepest staging point 130 meters). Going in is easy, I use my nitrox 36 until 35 m (yes, I run partial pressures of oxygen at 1.6 bar on open circuit). Then I swop over onto my bottom mix (I am going to avoid the discussion of which gas to swop onto, travel gas or bottom mix as that is an entirely different conversation). I know my gas consumption rate (I plan for 20litres per minute, I use around 12) and I know the time that I have allocated to get myself to 221 meters (13 minutes). This gives me the litres I need to get from 35 m to 221 m (at a conservative descent rate of 20 m/s) - namely 4900.The next step is to determine how I am going to carry that gas ? I physically can not manage twin 18’s so use twin 15’s with an assortment of side slungs. I like this approach because I protect my gas in nice neat and isolated containers where if something goes wrong with one, I still have others. At 250 bar, that means I can carry on my back 5600 litres BUT that gas has to also provide buoyancy for the whole dive so I can not plan to breathe my back mounts dry. I can however plan to swop onto a side slung at 35 meters and breathe that to 150 meters (a personal cut off point for managing stress and task loading).
That would mean that I have used approximately 1800 litres of gas from another source, which means I only need to get 3800 litres from my back mounts… to get there. Either way I do not have enough gas in my back mounts to get me there and back with a reserve. I know I need another side slung.Realistically I can not stage deeper than 130 meters (I do not have divers who can get that deep), so I will need enough gas to get back to 130 meters, which was 2500 litres. Each side sling manages 1800 litres of gas, so without a reserve, I need 2 and a half cylinders (I plan to be only able to get 1500 litres out of a cylinder). Translated this means that just to get from 35 meters to my first stage cylinder I need to carry a total of 7500 litres and that is without gas for buoyancy and a reserve. So, just to get there and back – if I were to breathe everything dry- would need a full twin set and two 10 litre side slungs. In order to feel safe I need my full exit gas in an isolated and protected reserve, i.e. 2500 litres which translates to at least one extra cylinder (total # of side slungs now required 3 or 1 to breathe in and two to get me out to my staged cylinders).
BUT I still have not accounted for the fact that I am not breathing my gas dry, so add another 1800 litres (an extra stage, total count is now 4 stage cylinders).
My gas consumption calculation requires that I have 7500 litres to breathe. I am planning on carrying 11250 litres which is a healthy extra 6300 litres over twin 15’s and four side slungs. Should I carry an extra stage ? Probably but that puts the descent at risk. Side slungs create drag and will slow me down. Am I happy with the risk ? Yes, because if I am coming out I have at least one if not two dedicated cylinders that I can use that I will not touch on the way down. I can also go straight to any number of staged cylinders as there is no swim required (I carry extra power inflator hoses and have independent bc’s inflated from independent sources to manage buoyancy risk).
Even if the calculations above indicate that in order to really be safe I should have an extra cylinder, my fail safe is my critical pressure. This will ensure that I leave with enough gas in my back mounts to get me out even though I have planned to use at least 3 extra cylinders (I build in a lot of fail safes). I know that if I am able to breathe my twin 15’s dry I will need 2500 litres to get to my staged gas (and that is at a conservative ascent rate, not an “oh my god things just when wrong, abort, abort, abort” ascent rate). That means I absolutely must turn my dive when my back mounts have 90 bar in them. Absolutely, because if I do not I absolutely do not have enough gas to live and will be doing my ascent on a wing and a prayer. Ad then there had better be a good reason why I pushed the limit so far because at that pressure in my back mounts I have no reserve and it is going to be real tight and real hard going to get to my staged gas.
My planned critical pressure is a more comfortable 140 bar. If I use gas at the planned rate (which is higher than my actual consumption) then I will get to my staged gas with 50 bar left in each 15 and three unused stages, oh and three stages that are full. Assume that something goes wrong with one stage, I still have two left. How much gas do I need to get to my staged gas at 130 meters, one cylinder. So to be in real trouble I would have to lose an entire back mount cylinder (I dive isolated manifold) and three side slungs. That scenario sounds highly unlikely but even if it does happen (gotta love Murphy), then I have one back mount and one side slung to get me back out. Those are odds I can live with.
Shew! Did you get all that ? It takes time to work out a proper gas management plan. It also takes an understanding of what the real, probably risks are. And there is a difference between a probable risk and a possible risk. I plan for probable risks because there is a good chance they will happen as opposed to possible risks which hardly ever happen. And then I work out what will happen if the unthinkable occurs… if I am happy with the risk, then I dive, if not I go back to the drawing board.Next week I will go into less extreme examples of gas management. Hopefully you have an understanding now of the importance I place on having enough gas, and how much thought goes into getting it right.

Cave Skills Part 2 - Too Deep (Helium vs Air)

2008-04-01T12:21:00.001+02:00

Interestingly Sheck Exley named the third greatest risk to a cave diver’s life as going too deep. This was the only explanation that could be found for a number of deaths where a continuous guideline and sufficient gas had been implemented. The magic number even back then was 40 meters but that is often (and especially in technical circles) ascribed to be too shallow – a number reserved more for the sport masses than the technical diving elite.

Every agency these days limits air dives to 40 meters. The technical agency’s still accommodate deep air diving with courses still available, but here the trend is toward mixed gas diving rather than the more macho (and dare I say it, old fashioned) deep air dive. There is some physiological support for the number 40 – it appears to be the depth at which deep water black out is experienced. Deep water black out is not a phenomenon we here much about these days even though it is not uncommon and has been deemed to be the cause of a number of ‘inexplicable’ diving deaths. Victims literally drown. To an observer they appear to be asleep with their eyes open and are immobile butt breathing. On examining their dives it is often found that these divers were on their deepest dive to date and that there was a significant jump between their previous deepest dive and the one on which the deep water black out was experienced. The most frightening aspect of a deep water black out is that divers who do survive do not recall any unusual symptoms prior to blacking out, which means that you as a diver never know about it!

So is 40 meters the dividing line between deep and too deep ? And is the 40 meter limit something that is reserved only for the non-technically trained ? The interesting thing about 40 meters is that it is the depth at which most divers (if not all) experience a narcotic effect that is strong enough to affect their control and ability underwater. This tends to give them a healthy respect for narcosis and at least introduce an element of caution should they decide to break their training and go deeper on their own (which is not something I sanction, but seems to be an unfortunate fact of life).
The problem with the 40 meter limit is its practicality. Inland dive sites like Wondergat and Badgat extend deeper than 40 meters as do the more interesting ocean dives and wrecks. However the ability to dive these sites within the air depth limit is restricted with the majority of dive sites and operators falling into the not ‘technical’ friendly category and either not providing helium filling facilities or actually accommodating the extra kit that a helium dive requires (twin sets and stage cylinders). This means that divers have to fill at home (Gauteng has two full time helium mixing stations with full boosting facilities) and sees many divers having to dedicate a set to a single helium dive and using an alternative set for normal air/ nitrox build up dives.
Diving legal has another set of complications, that of the expense of diving helium. Helium diving normally requires a twin set (or at least a H-valve and extra dv), decompression gas (read extra cylinder (s) and dv’s) and a helium enabled computer. All for an extra 10 or 15 meters of depth. Now compare that to a deep air dive where you use the kit you have do not need decompression gas or a new computer. The cost saving is sizeable in rand terms.

The expense of diving helium is not restricted to the cost of the extra gear, the big cost is the price of helium. It is an expensive gas made even more so with shop mark up’s. Not many shops believe in the principle of volume to offset a lower price (we most definitely do) and helium prices in the range of 45c a litre mean that a standard 20:30 fill (20% oxygen, 30 % helium which will allow you to dive within the ‘limits’ to 60 meters) will set you back around R750 (for twin 12’s – excludes oxygen and other filling costs that might apply).

If you have been able to extend your finances to proper helium kit the chances are still good that you can not dedicate a set to holding helium so at the end of your 45 minute dive you have no choice but to dump two thirds of your mix. Now compare that to R80 for the equivalent in an air fill (not to mention the fact that you do not need extra kit) and there is no wonder divers are still using air for most of their diving.

So should the air limit be extended to accommodate practicality ? I mean we all know that divers do not obey the 40 meter limit so surely if we should acknowledge reality and safely train divers to do what they are already doing, dive deep on air ?

There are a number of problems with this not the least of which is the number of times the ‘normal’ diver dives. I am a deep air diver (my personal limit is 60 meters) and for most of my open circuit career have dived sub 50 meters quite comfortably on air. But, I practice diving deep and if I am planning something that requires a 55 meter or 60 meter air depth, I build up to it… slowly. Deep air diving is not something you do once every three months. You do not simply throw your kit on and hop into the water. It requires discipline to dive deep on air. It also requires serious attention to your dive plan and in particular gas management. I know that if I build up slowly I can function at high narcotic depths. I know that I can build up narcotic adaption. But I also know that narcosis is deceptive. When I am diving sub 50 meters I pay a whole lot more attention than I normally would because I know that one of the effects of narcisis is that lovely “everything is just fine” feeling when in fact it is not. There are some dives where I get to 50 odd meters and feel totally crap so I turn around. I listen to what my body is telling me.

The problem with narcotic adaptation is that it can not be proved by science. Physiologically there is no adaptation and the effect you experience is actually psychological which means that the dangers of diving narced still exist, you just are more used to coping through the fog. It is important as a reader that you understand that whilst I understand why people dive deep air and I have and do dive deep air, it is not my preferred choice. I also avoid high narcotic depths when I have task loading or something complicated to perform (like navigating the jungle gym at Badgat). When I dive deep air I do it for a reason - in order to dive sub 150 meters I have to use gas mixes with a high narcotic depth ( (it is practically impossible to do it on a 40 meter EAD) which means I have to be able to function, think and problem solve under that stress. In order to do that I have to practice being exposed and I do so relentlessly. Now that I have moved onto my rebreather I have easy and cheap access to Helium I rarely dive with a narcotic depth deeper than 35 meters and as a result my diving is way more fun (ok, it could also be the fact that I am on a machine which is quiet and enables me to stay longer ). But not diving high EAD’s is going to be a problem when I want to go deep again because I am finding I am way more susceptible to narcosis than I used to be. If I want to go back to 200 meters (or deeper), I am going to have to rebuild that narcotic tolerance that was almost a decade in the making.
So is 40 meters the magic number ? Narcosis is debilitating of that there is no doubt.. The effects are also highly personal and there are few divers out there who have the physiological predisposition to manage it and manage it well (thanks to the very nature of narcosis there are a lot of divers out there who think they do though).

As a cave diver the situation is complicated by the fact that in a cave you have to retain control. You have to be able to dive without silting, you have to remember to lay a line that will get you out. You have to be able to think and reason and process underwater. It is not the same as diving where the surface is just above you. The gap between being safe and being dead is much smaller, there are more things that can go wrong. Here being narced is the difference between coming back or not.
Perhaps 40 meters is a good number. We have to draw the line somewhere! It is also the number that has been universally accepted so perhaps the question is not whether or not too deep is deeper than 40 meters, but rather whether or not you wish to bet your life on the fact that you can beat narcosis when it counts ?

Dives are more enjoyable when you are not narced. You are safer which means you are not a threat to your buddies when you are not narced, all valid reasons to subscribe to the teachings of the dead. Even more important is the fact that as a diver your life is worth more than the investment in trimix gear and fills. If you get it wrong there are seldom do over’s. Dead is dead!
The fact that diving deep on air is too easy and too accepted by the community at large is not a valid reason to choose to dive deep on air. As a cave diver we all have a choice - to contribute positively to our community and so build one that is responsible and safe or to promote practices that have been proven to be unsafe and kill divers. It is our responsibility to eradicate the misconception that diving deep on air is the kewl thing to do. It is our responsibility to create divers who can make informed choices based on fact and not ego!

Cave Skills Part 1 : Why Use a Line ?

2008-03-25T16:38:00.000+02:00

Thanks to pioneers like Sheck Exley cave diving is not as risky as it once was. His survey of caving deaths and the subsequent principles that every cave diver should follow was instrumental in eliminating the inherent risk of being underwater in a cave. Interestingly, the first contributing cause he identified was NOT using a continuous guideline (see the blog post, Blue Print for Survival). These days not using a guideline is the exception rather than the norm, but back in the early 90’s using your memory was an accepted alternative. Indeed there was a continuous argument between divers who preferred to ‘learn’ the system (memorise the way in and out) and those who relied on lines to get them in and out. With each claiming the others method to be dangerous.
Those who argued for memory maintained that if you lost the line you had no way of using visual queues to get yourself back onto it (and so out) as you never had to ‘learn’ the system. They also argued that using a line emboldened divers who then went further than they should which got them into trouble. When you dived using your memory (they argued) penetrations were slower requiring a number of dives in order to create the memory imprint of the route. This meant that risk was added slowly and so the chances were that should something go wrong, the diver would get out. The problem with this philosophy is that overhead environments are notoriously easy to silt out (not to mention the fact that light sources can fail). This meant that exiting the cave could often occur in the dark, which in turn meant that ‘learning’ the system only worked if you also learnt it in the Braille version.
No matter which way you look at it, the only reliable way of returning from a silt out (or any other emergency) is using a continuous guideline ? What that means is that you must be able to find your way back to the surface using either the line you laid or a line that is already in place. This line must at all times connect you to the safety of the surface, without any breaks or jumps. In an emergency all you should need to do is follow that line and most importantly, you should not require any light to do so (and preferably little effort and thought).
Practically this means tying off just before you enter the cave system (preferably where inquisitive sport divers can’t find the line and tamper with it or even worse, follow it into the cave). As the guideline is your life, you have a secondary tie off just inside the cave system or entrance which ensures that the line will always be there (just in case an inquisitive sport diver removes your primary tie off outside).
If you are lucky you will be the only dive team diving the cave system however more often than not, yours will not be the only line wending its way through the inky darknesss. In this instance there are two choices open to you. The first is to piggy back on the lines that have already been laid. This will require you locating the owners of that line and negotiating with them to use their lines. Some divers are happy with that, some not. And don’t be tempted to avoid the asking and simply use the lines. Divers can get quite territorial about their lines, not to mention the fact that you stand a real risk of the line being removed while you are still diving (can you imagine getting to a tie off and finding that the line you came in on is no longer there ?).
Quite a few divers avoid sharing and instead lay their own line. If there are other lines already in place then basic line laying etiquette dictates that you always lay your line under existing lines. The argument goes that should a team already be in the cave and need to exit in an emergency they will not know about your line as it was not there when they went in. Should they encounter a new line over theirs it could cause confusion and delays. If the line is under theirs they can ignore it and get out quickly and safely.
One other advantage of laying one’s own line is that you control the location and frequency of the tie-offs. The number and location of tie-off’s is one of the most frequently asked questions by new (and old) cavers. Divers tend to fall into two categories, either too many or too few tie offs. Nerves tend to increase the number of tie offs, while confidence tends to reduce the number. Both extremes are problematic. The line is there to get you out as fast as possible in an emergency where you have no visibility. Tie-off’s are obstacles which have to be negotiated. If the diver was meticulous the obstacle around which the line was tied off (normally a convenient boulder) is ‘invisible’ and the line flows in a single unbroken line straight past the boulder. However if this is not the case each obstacle has to be negotiated by touch in order to find the ‘exit’ point of the line. Not what you want in the dark.
The other problem that divers encounter when exiting a line is that of unforeseen obstacles or line traps. The rule of thumb is to tie off when you change direction. This will prevent the line from swinging into the wall and boulders or narrow crevices. This is easier said then done as direction changes can be subtle and often the only time you realise the line has moved is when you swim back on it and find it has tucked itself neatly into a crack. That is when you thank the heavens that you are not exiting in an emergency and make a mental note to add a tie off next time round. The trick is to keep looking back - that way you can see exactly how your line actually is lying and add a tie off it needed.
The next question normally asked is how many tie off’s is enough. There is no simple answer as that. A well laid line enables the diver to exit fast, in the dark. It also ensures that the line is always in an area a diver can pas through. A well laid line is also taut. Too few tie off’s can create a loose line as can badly tied tie off’s that come loose during the dive. Loose line can move…normally toward those cracks and crevices. It also is an entrapment hazard.
How do you know if your line is well laid ? The easiest answer is to ‘practice’ leaving on the line while pretending that you are doing so in the dark - that way you will see for yourself. Whether or not you are in the habit of ‘practicing’ on the way out, you should at least one official and real practice from your cave course. Even with a couple of practiced silt outs under my belt (and a handful of real one’s) I still find them stressful. My heart rate increases and with that comes a nagging doubt that this time something will go wrong. Do I have enough gas ? Will the line hold ? There is one place in particular that I do not enjoy, the restriction on 7th level (going to the old station) at Badgat. This is fine on the way in (a little tight but no problem if you are number one or two). But when you come back out it can be a complete silt out. Now I know that the line is well laid and that if I follow it I will be in the widest part of the restriction so there is no problem… but there is always that niggle, especially as you casually swim after what is after all a rather frail line that disappears into clouds of swirling silt. What if I take my hand off for some reason ? What if I do not find it again ? It is not simply a matter of placing your hand where you think you left the line. In a silt out you can never tell which direction you are in fact facing. It is easy to turn around without realizing it and at 80 odd meters gas is not something you take for granted (even with full conservative gas planning).
The panic never takes hold. I have been diving in caves for too long for that. But it is always there, a reminder not to get too confident. A reminder that the basics are essential if you want to survive and explore.

My memoir - Fatally Flawed (The Quest to be Deepest)

2008-03-19T12:56:00.002+02:00

When I finished my 221 meter dive I knew my next challenge would be writing the story of how I actually got there. There are just so many aspects to breaking a world record not the least of which is facing the fear of death and actually doing the dive. It is only when I look back at who I was and where I came from that I realise how far I had to go and how hard it was for me as in individual to get there. Just a word of warning, this post may fall into the category of (what has been described to me as) ‘fluffy’ (which I interpret as talking about emotions and philosophical concepts)....
A world record is an odd thing! It is yours for only a while and there will always be someone you do not yet know working their way slowly and inexorably toward breaking it. Once you have it, you are no longer invisible to the world and once you lose the protection of invisibility you are wide open to the judgements and criticisms of what can be an uncaring and disrespectful world. Whilst getting my record changed the way the world perceived me, it has taken much longer for it to change the way I see myself. From inside there is no glory, little fame and definitely no fortune!
The final incentive to write my story down was the day Dave (Shaw) died. Well not so much the day Dave died, but the story that unfolded afterwards. I found myself questioning the reason why divers choose to place their lives on the line for something so ephemeral as a world record. It became important for me to understand why I had made the choice to dedicate almost a decade of my life to this one thing. I realized that my perspective was unique – there simply is no other person in the world who has been an active participant in not one, but three world record dives. I was a support diver for Nuno Gomes (and indeed the lessons I learnt diving with Nuno have formed the basis for my technical diving career). I have a world record of my own and I was the person responsible for keeping Dave Shaw’s dive together when it all fell apart.
Love us or hate us, the divers who dare to go deep all hold an elusive attraction to the rest of the world (who choose to remain in the shadows of safety).
Should I have written this book ? I often wonder about that; about the self indulgence of writing down my journey and the permanence of capturing the experience. But I always wished that the divers who went deep and broke records (the true explorers) would write about the experience… and not just the facts and details, but what it felt like, what personal challenges they had to overcome. I wanted to learn from the divers who came before me.
Today the proof arrived which means I can start to sell my story and after almost three years of struggling to get this far, I find that taking the next step is far harder than I thought it would be. The responsibility weighs down on me. What if I have the words wrong ? What if my story has no value ? And then I hear a whisper, just a whisper, and it says, “Who you are is important! Where you came from is important! You have the right to exist! You have the right to your story. You have the right to have it told!”.
Without this book my record has little impact. It affects only me and the people I surround myself with. Perhaps…perhaps this story will connect with some-one else, who is looking for a way out, a way forward and perhaps, just perhaps, they will be the invisible face that breaks my record! I certainly hope so! Perhaps it will inspire you to tell your story, because just like mine, it has value and has a right to exist and be told.
And who knows, maybe now I will focus on book two, the manual to getting deeper that I wish I had had !
If you are interested in finding out more about Fatally Flawed go to www.tekdiver.co.za/Publications/FatallyFlawed.htm. The official launch should be in April

Blue Print for Survival - Top Ten Ways Cave Divers Die!

2008-03-17T12:41:00.034+02:00

The interesting thing about writing a blog is that one becomes aware of personal themes. As I write I find myself continually reverting to the concept of risk management. Sport diving is sold as a risk free endeavor that anyone can participate in... so safe you can allow your child to participate. Yet the statistics simply do not support this idea - accidents can and do happen.

As a deep diver people often assume that I like risky situations. The irony is that the opposite holds true - I am in fact totally risk averse. As a diver I actively avoid taking unnecessary risks. I am anal about planning, preferring to know and understand the risks that could kill me. Whilst I do not like risk, I do not avoid them and it is this conscious risk acceptance that I believe has been key to my success as a deep diver. it is this conscious acceptance of risks and their management that I believe every diver should incorporate into their diving.

The combination of training and experience is designed to enable you to identify and manage the most probable risks you will encounter underwater. These are risks that as a community we have regularly encountered. They are known and so we can do something to either eliminate the risk or succesfully manage your way through it.
After over two decades of technical diving, pioneers like Sheck Exley have established and proven the concepts and methods required to enhance (if not ensure) your safety underwater. In fact, it was a book by Sheck that formed the basis for the technical courses we know today. His analysis of accident statistics identified the patterns behind caving deaths and tragedy’s. making them visible and enabling conscious management there-of.

Sheck’s "Blue Print for Survival" identified ten elements that a cave diver needed to comply with in order to avoid the most common risks found in a cave:

- 1) THE GUIDELINE : In cave systems the most common cause of death was not using a continuous guideline from the entrance and not maintaining close proximity to that line.

- 2) AIR SUPPLY PLANNING : The number two reason for death was the inadequate provision of air/ gas. Gas planning should be based on at least the thirds rule and gas matching within the dive team.

- 3) TOO DEEP : The number three reason for fatalities was diving outside of individual depth tolerances, divers were going too deep, too soon and succumbing to amongst other things, narcosis.

- 4) PANIC : Coming in at number four was succumbing to panic. This can be avoided through effective training and continuous practice.

- 5) LIGHTS : Closely tied into most incidents was the inability to see (and so find your way out) which has led to the requirement of redundant lighting systems ( normally a powerful hand
held canister primary light with two stowed back up lights).

- 6) SCUBA : Many incidents could be traced to inappropriate equipment and the configuration there-of with divers diving with poorly serviced equipment and not ensuring full redundancy on life critical kit (every cave dive should be undertaken on at least a twin set with isolation manifold and two dv’s)

- 7) SILT : Yet another factor related to the ability to see. Here incidents could be attributed to the divers ability to reduce visibility through inadequate finning techniques that resulted in silt outs.

- 8) EMERGENCY PROCEDURES : In most incidents the divers had not practiced their emergency procedures which added another level of complexity to the situation that simply could not be controlled. Procedures such as buddy breathing and the ability to effectively communicate underwater were highlighted.

- 9) TECHNOLOGICAL EMERGENCIES : This factor talked to the divers ability to manage life threatening, predictable technological emergency’s underwater such as line entanglement and getting stuck. These are managed through practiced techniques such as the lost diver drills.

- 10) PHYSIOLOGICAL EMERGENCIE : The proactive management of physiological emergency’s (divers to be fit and proactively manage decompression risk, stress and narcosis)

These days all technical courses encompass every aspect of these basic principles. Indeed, it is not the norm for a qualified cave diver who follows these principles to die on a cave dive with most cave diving accidents and fatalities being attributed to sport divers who enter cave systems without training or appropriate equipment.
The unfortunate part of technical diving these days is that it as become too safe and as a community we are becoming too complacent. It is too easy for divers to apply the 'rules' on course and then ignore them thereafter. The problem is that every time they get away with it, they get bolder! As Nuno Gomes often says, there are two types of divers, old divers and bold divers. There are very, very few old bold divers.
The question you have to ask yourself as a diver is how you would like to die (because the only thing that can be guaranteed is that you will die, all you do not know is how and when) ? Do you want to be another statistic ...a diver who refused to listen and took shortcuts and so died ? Or would you rather be the diver who understood the risks and actively managed them ?
How often do you take shortcuts ?

One SPG or Two or Practical Risk Management

2008-03-11T10:20:00.000+02:00

. Technical diving is not a world of absolutes. We can only plan for and predict a relatively small subset of all the possible options. With the right combination of training (or skills) and equipment one attempts to accommodate all the probable risk scenario’s, so for me it is important that as a technical diver you understand the decisions you make. The Hogarthian equipment configuration was designed to solve a particular set of risks, and it does so quite successfully. However that is not to say that it is the only solution.
Take for example the decision made to have only one spg (pressure gauge) on the configuration. The argument goes that you are diving open manifold, so one spg will tell you the same thing as two. The risk that the Hogarthian diver is more worried about is an spg failure. In their world, spg’s have a tendancy to regularly fail resulting in a catastrophic loss of gas (which then requires isolation and termination of the dive). Now when I listen to this scenario I start to get uncomforrable. Yes, I understand the risk of an spg failure resulting in a catastrophic loss of gas, but I protect half my gas, so it is not really an issue for me. What worries me more is having to leave the dive with absolutely no idea how much gas I actually have. The Hogarthian diver argues that you are leaving the cave, so it does not matter. You were diving on thirds so you must have enough gas in both cylinders left. Which raises the question how ? How do I know I have enough gas ? To which they answer, it hardly matters because if you don’t what can you do ? You can not magically find more gas ?
It is at this time that I nod sagely and walk away… to my twin set with two spg’s. Every diver has a hierarchy of risks and for me, I can not rank the possibility of an spg above not knowing how much gas I have. Why ? Because I want to survive! I want options and when I know how much gas I have I have the ability to make better decisions. How I exit will depend on how much gas I have. Think about it. If you have 50 bar are you going to swim fast and so increase your breathing rate ? Or are you going to take the time to slow everything down and resort to controlled methodical swimming that focuses on getting the maximum distance for the minimum breathing ? I know I would! Now, if you don’t know, but think that somehow magically you have enough gas are you not just going to exit as normal without any mind to gas management and so face a much greater risk, finding out that your last breathe was the last you will ever take. Now your only option is to hold your breathe and see if you can make the distance. Not a chance I wish to take.
As a diver I want as many options underwater as I can get. I am not advocating that as a diver you should throw away the concepts behind a Hogartian configuration, just that you take the time to think about why it is set up the way it is. What risks are they mitiating ? Are they your risks ? Are they probable risks on the dive you are planning ? If yes, then you have no need to make changes. If no, well hopefully you now have a better idea how to make changes.

Open or Closed Manifold ?

2008-02-27T15:19:00.000+02:00

In the last blog I talked about Hogarthian equipment configurations. It is one thing knowing what a Hogarthian configuration is, quite another to adopt it into your diving philosophy and equipment configuration. What I like about Hogarthian is that most of the hard thinking has already been done! You are being handed a solution that not only has been thoroughly thought out, but has been a decade or more in the testing.
My biggest issue with Hogarthian is that it takes away a certain degree of personal responsibility … all that thinking has been done for you. This can lead to blind adoption and a false sense of security. What do I mean ? Well blindly adopting anything (be it a philosophy or an equipment configuration) will only get you so far. Sooner or later you will come up against something that the designer had not thought about or considered. It is at that point that the system has the potential to fail spectacularly. Having said that, there are not many situations that would fall into this ‘new’ category, especially if your technical diving is within agency limits and well explored dive sites. The problem comes in when you decide to do something that has never been done before.
Key to any successful exploration is the ability to assess the individual risks of the situation you are trying to ‘conquer’. When new risks are identified the entire process of planning a dive needs to come under review and if required, adapted to ensure that every probable risk is mitigated. For me, that means adapting my equipment configuration and that often takes me away from pure Hogarthian. It needs to be said that if you are new to technical diving Hogarthian will get you far and you will probably never need to contemplate changes. However, there is still a school of older, hard core divers who are set in their ways and believe that their way of diving is the best. Which is ok, every diver has the right to choose for themselves (after all the person who pays the price when it all goes wrong is that diver ) however many of these older divers have some influence over the next generation. As a result many old school ideas are still alive and well, when they possible should not be.
My personal equipment configuration was designed to do one thing - gett me to 200 meters or deeper. It was not something that I arrived at on the actual expeditiaon, but rather was prepared years before. This meant that every dive I did was a build up for that elusive deepest dive. The configuration I chose mitigates my biggest fear and risk, namely running out of gas and to that end I quickly (as soon as they became available) moved to an isolation manifold. However, I do not dive my manifold open, nor do I dive with a single spg or both dv’s coming over my right shoulder.
My choices were made to accomplish 4 things:
1) Safeguard at least one half of my gas supply,
2) Enable quick identification of the gas supply that is at risk (left or right cylinder),
3) Limit my immediate task loading and ensure that I am able to retain buoyancy and line control and
4) Ensure that I always know how much gas I have left so that I have the option of a more aggressive survival strategy.
I am not trying to prevent gas loss, but protect what I have and there is the big difference. I am also managing another huge risk, a bottomless, fast descent which is a characteristic of a deep bounce at Boesmansgat. This is the world’s 3rd largest water filled cave and when you do dives deeper than 60 meters you have 200 meters of black water beneath you. Your only connection to light and home is the shot line, that hangs in the middle of this vast black expanse. If you come off that line there is a very, very good chance that you will not find the entrance again.
When I plan these bounces I visualise what will happen in say the even of a catastrophic gas failure. I am descending the shotline… fast. I hear a flood of bubbles. I can’t let go of the line, so have to first gain control (slow or stop), then identify the side that is causing the problem (left or right). If I am close to my target depth the situation is even more critical because I can not afford to go deeper than planned without throwing my decompression out and creating a possible situation later on that I will not survive.
As I have my dv’s over each shoulder, should the problem be with an SPG or power inlator or second stage locating the source of the problem is fast and requires little thought. I like little thought, because initially a large portion of my concentration is busy maintaining control and keeping myself safe. Once I have worked out what the problem is and have control, I can shut the appropriate valve down and assess the damage. At no time have I lost control or lost more than one side of my twin set. I still have buoyancy and I am still on the line. At the most I have sacrificed one half of my gas, and I have already planned to lose that so I have plenty in reserve.
Now the counter arguments to this strategy are that it should not take me more than 30 seconds to isolate. But that is a lot of air you lose, out of both cylinders when deep, possibly everything. In any other situation I agree and in fact when I do normal technical dives I tend to relax and dive my manifold open because when something goes wrong I can immediately focus on the problem without complicating the situation. However, when something goes wrong on a deep bounce there are a whole lot of things that have to come before I can safely get to isolating. And all the while I am losing precious gas.
They also say that diving closed manifold adds to my task loading because I have to change dv’s regularly in order to ensure that each cylinder has more or less the same amount of gas in it (if you dive single cylinders with no balancing of pressure open yourself to the risk of breathing one cylinder down to reserve and then losing the full cylinder, which means that you have no gas. If the pressures were balanced then you would have had at least half of the gas you needed).
I do not agree that the task loading is a significant enough risk to avoid and have been changing dv’s for over ten years so it is no longer something I have to think about. I also plan for dv changing as well as to not change dv’s in the last 50 meters of a deep bounce (accepting the risk of a single cylinder having a significant difference in pressure from the other).
I already know that it will take me time to get to the point of isolation just based on the dive I am doing, add to that the time it took to identify the problem and even if you could isolate in 30seconds, you could be closer to a minute in getting that manifold closed. Every second is precious, a minute… that is both my back mounts. That is if I can actually get to isolating and am not in the middle of a task loading crisis (events never happen one at a time). The longer I delay the less air I have. My back mounts inflate my wings, no gas means I now have another issue, I have to hook up my wings to an alternative inflation source, all the while hanging from a line I can not loose. When my manifold is closed there is no stress, at the most I am going to lose one cylinder and I have planned to get out after that.
I doubt that I will ever be able to rationalize or practice my fears away and fully trust the pure Hogarthian configuration. My diving career has taught me to take responsibility for myself and to accept all the consequences of a dive. That means I need to have thought it all the way through, challenged all the standard ways of going about things and then assessed the risks for myself. I have no intention of re-inventing the wheel, but I want options. I have also found that in many cases people do not understand the motivation behind a decision. Why dive with an open manifold. By making it my business to understand the why I give myself the option of making changes and it is that ability that enables me to solve problems that other divers on standard configurations have been deemed impossible. It is not an approach for everyone… but it does have its advantages.

What is a Hogarthian Equipment Configuration ?

2008-02-20T16:33:00.036+02:00

The term “Hogarthian diver” generally refers to the minimalist diving style devised by William Hogarth Main who believed that if a piece of equipment isn’t needed, it’s a liability so don’t take it. As a result, Hogarthian divers strive to “eliminate the unnecessary while configuring the necessary in the most streamlined manner possible”.

Each piece of equipment is chosen not only in relation to the need if fulfills, but also with regard to how it ‘fits in’ with other equipment elements. As a result the diver creates a harmonious system that functions cohesively. Any decision to change one aspect of your configuration must take into consideration the entire system and normally adversely affects the workings of another aspect.

Within South Africa, the community is divided with older divers still relying on independent twin sets, short dv hoses and helmet mounted lights. Most have adopted the standard technical wing and backplate configuration (although just the other day we saw a diver doing a 100 meters with two independents strapped together with ratchet straps and a standard bc). This often results in a configuration more like a Christmas tree, with hose routing willy nilly and additional features like valve cages adding extra snagging risk. Short hoses are non-buddy friendly in event of an emergency (and you certainly would not want to exit through a restriction on one) and helmet mounted lights tend to do little for improving visibility in the water whilst at the same time blinding fellow divers.

Now compare all that to a Hogarthian configuration, which (with only the addition of an drysuit inflation bottle and a pee valve) set the world cave-diving penetration record of 4.3 kilometres at WKPP). Admittedly Nuno Gomes is one of the more famous strokes (non DIR/ Hogarthian divers) and he holds the depth records for both sea and cave, but anyway!

HOGARTHIAN KEY CONCEPTS :
- To reduce unnecessary energy consumption which will increase gas consumption. This limits the divers range and introduces a higher decompression risk
- To create a clean configuration that is snag resistant and drag free (see energy consumption)
- Reduce drag (no weight belt, limit bc inflation at depth) (see energy consumption)
- Reduce unnecessary task loading (see energy consumption)
- Your buddy always knows where everything is, which simplifies emergency situations and improves survivability.

BC CONFIGURATION
The concept : to create a streamlined, clean configuration with a clear and webbing that is tight and close to the body with no projections or dangling straps.
This is accomplished by : a standard twin set, with a single wing and back plate. Webbing is continuous (reduces the risk of buckles failing). Three D-rings (one at each shoulder and one at the left hip, held in place with weight retainers) provide the means to attach ‘stuff’ with a fourth small D-ring far back on the crotch strap for cave reels and lift bags.

WEIGHTS & SUITS
The concept : to avoid the addition of a weight belt. This reduces effort as a result of increased drag, improves comfort and reduces the chance of problems in event of an accidental release.
The diver relies on the weight of the steel twin set and back plate no weight belt is required and if it is, a long lead weight is bolted to the backplate between the tanks. Only trimlam drysuits are allowed so that additional weight is not required. This removes the need to over inflate the wing at depth (as a result in buoyancy shifts due to neoprene compression). Your dry suit pocket stores everything that is not clipped to your harness (i.e. cylinders, back up lights, reels and smb’s).

GAS SUPPLY
The concept : to reduce task loading, minimize the risk of air loss and reduce snagging risk.

Twin cylinders are connected via an isolation manifold that is always dived open and so allows access to both cylinders whilst enabling the diver to manage malfunctions. As the tanks are dived open, the multi tasking associated with swopping dv’s is eliminated as is the risk of uneven gas consumption.

Two dv’s are carried - the primary from the right cylinder (and over the right shoulder). This feeds a second stage on a 2 m hose as well as a power inflator. The back up dv comes from the left cylinder (over the right shoulder) and feeds a second stage on a normal length hose as well as the drysuit and an spg (contents gauge). It is held beneath the chin by surgical tubing. The spg is clipped off to the left hip D-ring.

The primary rig is breathed on the dive and donated in an emergency. The hose is stowed down the side of the right tank (behind the wing) then at the waist, brought forward, passing between the body and the bottom of the light canister, then proceeding diagonally up across the chest, over the left shoulder, around the back of the neck and the into the mouth. A clip on the hose next to the regulator allows it to be 'parked' it on the right shoulder D-ring when not in use.

LIGHTS
The concept : to reduce drag, optimise light and eliminate blind buddy syndrome

A single primary light is carried with the standard two redundant back up lights (both stowed on the harness strap). The primary light is a canister type that is attached to the right waist strap, as far back as it will go (preferablyup against the backplate) to reduce drag. The waist buckle of the harness pulls tight against the light canister – securing not only the waist strap but also the canister.

STAGE CYLINDERS
Cylinders are clipped off between the D-rings at lefthip and left shoulder.

That in a nut shell is what Hogarthian is all about! In my next post I will look why I have not dived this system and what still feels odd to me. But then again, I have been diving for a while and change does not come that easy :)

Solo vs Buddy or should it be Self Reliance ?

2008-02-11T15:54:00.001+02:00

One of my favourite topics is that of solo diving and like most things in diving, there are strong advocates for and against. Before I jump right in let me explain how I define solo diving… being in the water alone, with no other diver or buddy. If something goes wrong on a solo dive (even if it is out of your control) the only person who can get you out of the dive is yourself. With a buddy (the argument goes), when something goes wrong there is someone who can help out and so your chances of survival are improved.

I have always been a strong supporter of solo diving simply because I believe solo diving forces an individual to take full responsibility for their dive. Because on a solo dive when something goes wrong you only have yourself to blame, you tend to be a whole lot more thorough with your planning and preparation and because you are paying more attention you are a far safer diver. In fact, I would argue that diving solo makes you a far more competent diver.

Now you may think that as an advanced or experienced diver you plan properly and take nothing for granted… but I would like you to think about that for a second. Sport diving ingrains in the diver a belief that their buddy will get them out of trouble. As a sport diver you are never alone, nor are you ever fully responsible for the consequences of a dive. Now, if you believe that there is always someone to help you, how thorough is your preparation really going to be ? It is human nature to be slightly sloppy, after all, it does not matter if there is someone there to save the day! And if things go wrong there is also some-one else to blame and take responsibility. With the buddy system it is far to easy to assume that your buddy has thought of everything and knows what to do. Which means you both get into the water unprepared.

The facts are that no single individual is omnipotent (and your buddy certainly isn’t). In fact, there is a good chance that his ability in an emergency is nowhere near your own. Perhaps it is not a good thing, but when it comes to my live I do not trust other people underwater. My thinking goes like this - should I die (or get badly injured) would it be valid to blame my buddy (or instructor or Dive Master) and say that it was not my fault but theirs because they did not plan properly or were not capable ? No! It would not because there was something I could have done but neglected to do because I was lazy and preferred to make it someone else’s responsibility. At the end of the day it is my life and I am the one that should accept responsibility for that life. Besides, you can never tell who will step up and manage a real life crisis. Invariably the person you expect to save you, is the one that crumbles under pressure.

The irony is that whilst I consider myself to be a solo diver, most of the time (and especially on extreme dives) I am not actually alone in the water. On my 220 meter world record dive I was alone for a little over 15 minutes before meeting up with my deep support divers at 120 meters. From then on (5 and a half hours) there was always some-one in the water with me. Not that they did much (I rarely ask for assistance). It is however comforting to know that should I need it, they are there to lend a hand.

You can argue (and quite effectively I might add), that if no single individual is omnipotent, then neither are you as a solo diver. Which is were I think the argument for pure solo diving starts to fall apart. I have had the experience of being stuck at 152 meters in a tunnel, a location that my nearest support diver could not reach. My fin caught on the guideline and I was not able to get reach my foot to get myself unstuck. This was probably the first time on a dive that I was able to justify the existence of a buddy. He would have been easily able to sort the problem out. I almost did not make it out and only did by leaving my fin behind.

This experience and that of Dave Shaw (who also got stuck on line although that was not deemed to be the ultimate cause of his death and was rather believed to be the final straw) has made me question whether or not there is a middle way, neither pure solo nor pure buddy. The thing that I fight for in solo diving is the personal acceptance of responsibility and the fact that each diver has no-one else to blame. This self reliance and self responsibility forces individuals to pay more attention and be more meticulous and seems to only arrive when all other options are exhausted and you are diving alone underwater. In theory it should be possible to arrive at the same result within the buddy system. After all, we dive with full redundancy in everything but the one thing that counts, our minds….and that is what a buddy provides (thanks to Dr Jack Meintjies for this phrase).

No matter how you look at it solo diving will always remain highly dangerous. It is not something that can be taught, being more a lifestyle than a predefined course. But, what we can teach is Self Reliance and that for me is the perfect compromise. I retain all the benefits of solo diving confer with all the benefits of being with a competent buddy. Yes, there are still situations where having a second diver increases the risks (diving deeper than 150 meters is one of them), but for day to day dives incorporating the self responsibility and self reliance into your buddy system will radically improve your safety underwater (and remember, most accidents happen shallower than 50 meters…so you everyday sport dive has a much higher risk than our extreme dives)

Thank Heaven for Support Divers

2008-02-05T15:20:00.000+02:00

A successful deep dive (be it to 100 meters or to 300 meters) revolves around three things; the ability of the deep diver, the thoroughness of the dive plan and the effectiveness of the support. The role of the support team is often neglected (even by experienced divers who instead choose to rely soley on their own abilities to get themselves out of the water when things go wrong). Now I am a strong advocate for solo diving BUT having said that, I also believe strongly in stacking the cards on your side. On any dive (never mind an extreme dive) things can go wrong that are simply beyond your control. It does not matter how thorough your dive plan is or experienced you are as a diver, you can not control everything. It is then that an efficient and reliable support team can mean the difference between life and death. Whilst I prefer to do my deep push solo, the actual time I spend alone in the water is as little as possible, with my first deep support diver meeting me from 100 meters (deeper if I can find qualified divers). This is a strategy I picked up from Nuno Gomes, and indeed, the use of support divers is one that other highly successful deep teams such as WKKP use.
If you are still unconvinced, let me tell you the tale of two highly experienced deep divers, Dave Shaw and Don Shirley. Until their last dive (the ill-fated recovery of Deon Dreyer from 272 meters) they believed in no support, preferring to rely on their own skills underwater. It would be fair to say that they did not believe there was anything of value that a support diver could add. Their choice to add a support team to the attempted body recovery was a combination of logistics (the divers were there to get the body out) and pressure from the police and other professional support teams. One of my strongest impressions as surface marshall on that dive was that we were there more for window dressing than any real belief that we could make a difference. Yet, when Don suffered his near lethal ICDS hit (inner ear bend) at 50 meters it was the support divers who made the difference and ensured that he made it to the surface. Most of the divers who were there strongly believe that Don would not have made it back by himself. It was the support divers who put him onto the right deco gas (he had bailed from his rebreather onto the wrong mix) and made sure he was doing the right deco stops. They were also making sure he remained upright and on the line. It took hours before his nausea subsided and whilst he was always conscious, his ability to write and respond straight after the hit were seriously impaired. Don’s description of how seriously impaired his abilities were was chilling the next day. His focus was on just the next breathe! And it was one that required all his willpower and attention.
Not every extreme diver relies so heavily on its support divers. When things go according to plan their job is mundane, fetching additional weights to the diver, getting him gas and arriving with warm drinks. Boredom and cold are the support divers enemies. Until things go wrong.
The first question I ask someone who is keen to support is this, “Are you prepared to leave me behind, knowing I will die ? Are you prepared to be on the surface when I do not come back ? ” Most support divers never think of how they will feel if things go wrong, especially if they are there at the time. The truth is that there is little they can do, especially if the diver is unconscious and not breathing. If the deep diver gives up or if it is simply not meant to be, the only thing a support diver can do is get the deep diver to the surface where (hopefully) professional medical support is waiting.
Decision making is simple, you avoid what will definitely kill the diver (leaving an unconscious diver who is not breathing in the water at 40m will definitely kill him, bringing him to the surface and skipping all his deco just probably will kill him and probably, no matter how small a chance, is worth fighting for). If the diver is still breathing, then the support divers job is to do his dive for him. His chances of survival increase for every minute of the deco that he is able to do, and that is the chance that the support diver gives.
The role of support is one that comes with a large amount of responsibility. As a support diver, you need to understand the dive your deep diver is doing. You need to know what his gases are, when he is changing and you need to have discussed with the entire team what action is expected of you if things go wrong. And as a support diver you need to know that all that is expected of you is your best, nothing more. At the end of the day your deep diver’s life is not in your hands, but in his and dare I say it, God’s.

The VR3 vs the new X1 (aka Picking a Helium Computer)

2008-01-28T17:20:00.000+02:00

Want a VR3 but can’t afford one ?
There are a number of items that seem to be permanent fixtures on any technical diver’s wish list… a dry suit (because 3 hrs in the water is a long, long time and hypothermia is still not a fun way to spend an afternoon), a rebreather (come on, you can admit to wanting one, even if you currently think all rebreather divers are elitist because they can stay down for longer and do less deco) and of course, a Helium computer.
Up until the arrival of the VR3 if you wanted to dive Helium you had to do it the old fashioned way - with tables you cut on land using something like GAP or V-planner. This meant that you had little flexibility in the water, especially if something went wrong. Now I guess I need to confess up front that I sometimes fall into the category of old fashioned and suspicious of ‘new;’ things when it comes to some aspects of diving. I had heard about VR3’s but did not really see why I should drop 17k on one. Especially as I would need two (in case one did some unplanned load shedding (South African joke… we are going through power cuts thanks to the lack of planning by our national electricity provider)). I did not need a fancy computer that did all that for me underwater. I already had a decompression program and as all deep diving needs up front planning, what was the point ? Dynamically diving helium just seemed like a recipe for disaster. I could see diver's willy nilly doing 2 hour dives just on their computers and running out of gas having not done any up front planning.
Then I went as surface marshall on Dave Shaw’s dive and was blown away by the sheer power and flexibility of the VR3. Every diver had one, and thanks to those elegant little devices, I was able to leverage every spare minute out of every spare diver I had. I needed to. When Dave did not return all the deep support divers overstayed waiting for him (thanks to their VR3’s (and their rebreathers, but once again, that is a different story)). When Don Shirley blew his electronics at 127 meters and did his emergency ascent, followed by a near lethal ICDS hit (long explanation short, an inner ear bend) the day really fell apart. Out of 8 support divers I had 6 that had been to 100 meters and deeper, leaving me with two divers who had not started their dives and now had to manage continuous support for at least 4 hours (which was how long it would take to get one of the other guys out of the water and some surface interval time). Oh, and they had to do the first three hours of this in the 30 meter to 50 meter zone. Suddenly the idea of a VR3 was not so silly. I bought one.
And boy has it changed the way I dive. The decision to dive helium as opposed to air has always been one I have left to deep dives (deeper than 65 meters). And because of the inconvenience of having to bend my normal computer, cost, planning etc the number of deep dives I used to do was minimal. These days (thanks also to a rebreather which makes the cost of helium affordable as I hardly use any on a dive) my VR3 means I get to dive more. I need another one in fact, if it was not for the price.
As a technical dive school Liquid Edge firmly believes in two things. 1) Removing limits (Score one for the VR3) and 2), Finding and providing dive gear at affordable prices. Which is where VR3 loses out. If you were to ask local shops for a price on a VR3 you should expect an answer of around 17k for a ‘fully loaded’ (rebreather, helium capable) VR3. If you balked at that (which I certainly did) and started to do some internet research you would find that divers warehouse in the UK (http://www.diverswarehouse.co.uk/) will sell you the same item for £749 (excl UK VAT). Now, even at the pound exchange rate (R14,3 on a good day), shipping (add £70) and Vat on this side (14%) you are looking at R13,400. That is way more reasonable than 17k.
But we wanted to know if their was an alternative and guess what we found ? A brand new Helium computer that is looks like it out classes VR3 in all aspects, not the least of which is price. The Liquivision X1 (http://www.liquivision.ca/)
Here is a quick product comparison:
X1:
- Downloadable (VR3 - Add £80)
- Depth Rating 350 m (VR3 - 150m)
- Tested to 450m
- Sealed unit (VR3 not)
- Uses either Gap or Vplanner (VR3 uses decoplanner)
- Tap Switches with x, y axis (VR3 is push buttons)
- Rechargeable Battery (40 hr life) (VR3, user replace'able)
- Upgradeable from internet (VR3 - not)
- Price R13k (VR3 R14.7k)
(Please note prices above are based on R7.40 to the $ and R14.3 to the £)
Finally, some choices! I have mine on order and will certainly tell you guys all about it when it gets here.

The Myth of the Deep Bounce (How Easy is Soap on the Rope ?)

2008-01-23T11:26:00.000+02:00

As you may (or may not) know, I hold the woman’s world record for the deepest dive (221 meters, set at Boesmansgat in the Northern Cape). The one thing that I did not expect after achieving this were the mixed reactions I received from fellow divers.
There are definitely two camps, those that are fascinated and excited and those that do their utmost to minimise the achievement. From that camp has come the term ‘soap on a rope’ which is meant to indicate that there is nothing very special about doing a deep bounce and that anyone can do so. If you were a real deep diver and explorer you would be swimming off the line and spending time at depth, or so the argument goes.
Which started me thinking, “Is a deep bounce dive a cop out or is it something to be proud of ?”
The existing deep records require that a diver to descend (normally as fast as they dare) to their designated depth, spend a minute or less (to make sure depth gauges record the depth achieved) and then return. The actual exposure to depth is measured in minutes, if not seconds. And I guess the uninformed can be forgiven for taking the dive at face value and declaring that it is hardly difficult. Yet if one looks at the survival rate of the divers who have attempted this so-called ‘simple’ dive, a different story emerges.
Firstly the number of divers who have made it below 250 meters is limited. I count only 5 who can justify their claims (through a combination of gauges and tags retrieved). They are Nuno Gomes (the current world record holder for depth and deepest cave), John Bennett (the first man to break 300 meters), Sheck Exley (father of deep cave diving and original record holder), Jim Bowden and rebreather diver Dave Shaw. Of these every one had issues, ranging from serious inner ear bends, minor elbow bends and inner ear problems.
Every one of these divers was after one thing, finding out how to get deeper and back. None attempted to swim at depth. None at least until Dave Shaw. Dave was an Australian rebreather diver who I met on my world record dive expedition. He was planning to try for 300 meters (a new cave record) a couple of days after my dive. Instead he found the body of Deon Dryer. His plan saw him descend down the shotline to the bottom of Boesmans (about 260 meters) and then swim off to find depth. The dive required only a short swim at depth and while he was successful the first time, he never made it back to the main shotline on his second dive.
Admittedly these divers were pushing the edge of what is known, so how much safer are bounces in the 200 to 250 meter range ? One of South Africa’s more experienced instructors Don Shirley can attest to the effects of a simple and easy soap on the rope that went wrong. When supporting Dave Shaw he descended to 227 meters (according to his VR3’s) and barely made it back alive... and that was a dive not much deeper than my soap on the rope record.
None of which supports the argument that ‘anyone’ can bounce depth and survive now does it ? After all, these are some of the most experienced, accomplished divers in the world and their track record tells a completely different story.
So what is stopping deep explorers from spending time in the sub 250 meter zone ? And what makes bounce dives so deadly, even though their execution seems to be so relatively simple ?
The first problem is gas. As open circuit divers you only have so much gas to take with you which means that a couple of minutes is really all the time you have at depth (the deeper you are the more gas you use on a single breath and the more gas you need to get there, never mind build in safety in case something goes wrong).
The second problem is that tables are not designed for either depth or swimming. On a bounce you can keep your heart rate low and so minimize your absorption of helium and nitrogen. However, when you swim you change the absorption characteristics of your body… taking in more than the tables are expecting. We get around that by building in fat, an extra minute at depth that you have no intention of spending, plenty of deep stops of at least 2 minutes). But still, the resulting deco profile is an educated guess. The only way you know if it will work is by doing the dive.
Which leaves us with the one problem that has not been solved, accurate decompression profiles that predictably and repetitively eliminate bends. Right now a simple bounce is just impossible to predict and whilst spending time ‘exploring’ sub 200 meters is every diver’s ambition, it adds a whole new level of complexity to an already complex equation. Don’t get me wrong, I love complexity. I love problems that are deemed impossible. For me that just means that someone has not thought about it the right way… and maybe I can.
So are deep bounces minor dives that any diver can tackle ? No! Deep bounce dives are hard! To that the divers who have been there can attest! It does not matter if you spend seconds or minutes, the physical and mental challenges remain! Next time you hear a diver making light of these dives take a second. It is easy to belittle another’s achievements. Indeed, it seems to be a norm in society and not restricted to deep diving.
Aha, you are saying. ‘Of course she is going to say that, she is one of the people who get belittled!”
Let me tell you a secret. What I have gained from my world record is not recognition, fame or glory. Those may (and probably were) reasons that got me started, but they are not strong enough motivators to keep you going when everything goes wrong. It is not enough to be able to dive, you have to find support divers and money and equipment. You have to learn how to dive deep, safely and there are no courses out there to teach you and even fewer experienced mentors willing to take you under their wing.
I may have started out wanting a world record to prove something to the world but what I found out was that I was actually proving something to myself. The journey to a world record is highly personal and very, very internal. The value I attach to my record has nothing to do with your opinion of it (or me as a result). Thanks to this one relentless desire of mine I found out who I could be.
I also learnt that limits are choices and that the only limits that exist for me are the one’s I believe in. There will always be people trapped in a world defined by limits and they will always be the people who belittle other’s accomplishments, and there will always be people who want something enough to go ahead and do it, in spite of what the world around them thinks. It does not really matter if the limit you are pushing is the world’s or your own. Is the personal challenge any easier for people who climb Mt Everest today ? Even with modern technology and sherpa’s many do not make it.
I think Nelson Mandela put it best, ‘And as we let our own light shine, we unconsciously give other people permission to do the same.” So next time you hear a story that makes less of an achievement, take a minute… and put what you are hearing into perspective.

Advanced Nitrox - Necessity or Luxury ?

2008-01-21T16:33:00.000+02:00

As a normal sport diver your limits are 40 meters, no decompression diving (NDL), which gets you to most places and on most dives. The only thing is, at that depth you are at the limits of air and even on nitrox, can not spend much more than 8 minutes exploring. Now I don’t know about you, but no reef is worth the price and effort for 8 minutes, make that 25 minutes and we are starting to talk business. Which is exactly what you could be doing if you were able to do decompression.
These days most divers have a Nitrox certificate, so most of you already know what a difference nitrox and reduced END’s (equivalent narcotic depths) make to the quality of a dive - not only do you get to stay for longer before hitting NDL limits, but you physically feel better after the dive. Advanced Nitrox is a logical next step. For some it smacks too much of technical diving, which is in turn associated with danger, risk, complication and money. However, investing in an Advanced Nitrox course is not as pricy as you may think. Nor is it a choice you should only be making if you are thinking about becoming a deep or cave diver.
This a course that improves your skills and safety underwater without unnecessarily increasing your risk or requiring a hefty bank loan and spans of heavy, complicated gear. Interstingly, this course is not considered technical by the agency’s, and is classified as a ‘sport’ course.
Lets take a look at the gear requirements. You can use your existing sport set up (single cylinder and jacket bc) with one addition, an H-valve that allows you to attach two dv’s to your cylinder. You will also learn how to manage one extra cylinder for decompression. Easy, simple and very, very do’able. Or you can be more adventurous and replace your jacket bc with a wing and backplate (you can still use single cylinders). A lot of people in fact prefer this configuration as the backplate and harness system is clean, with no added bulk in front of you and lots of space to clip things. The cost ? Around R2,7 k for a Frog wing and backplate.
The course itself normally takes 4 days. At the end of it, you will know how to safely do decompression dives and manage your gas ensuring that you have more than enough to do your bottom time and your decompression and manage if something goes wrong with your buddy. I should mention at this point that as a CMAS diver, I started off on my open water one course learning decompression so for me it is completely odd for divers to have to get out of the water in order to avoid decompression. With the arrival of deco computers divers often make the mistake of thinking that they do not need a course to teach them how to do deco dives, their computers will do it all for them. But, did you know that divers still bend on computers ? And what happens when your battery goes flat, mid dive ? Do you understand how important the stops are and how much flexibility you have in maintaining your depth for those ? Do not get me wrong, decompression diving is not excessively dangerous, not at sport depths. Especially if you have had training.
There is one other important aspect of the training that is perhaps even more important than removing the no decompression limit. This course ensures that you recognize and face the real risks of diving and then ensures that by the time you are finished you have practiced managing those so many times that you can easily and quickly get yourself to safety.
This shift from a buddy to self rescue is fundamental and as far as I am concerned the biggest benefit. It worries me how easily divers place their lives in the hands of instructors and or buddies, with no proof that either are capable of managing a catastrophe underwater. And the thing about situations underwater is that you have very little time to get it sorted. How you react is critical! The calmer you are, the more practiced you are in the skills, the better your chances of making it back to the surface. Personally, I do not allow myself the luxury of having someone to blame when something goes wrong underwater (and if you dive long enough, it is always when, not if something goes wrong). It is my life and I take full responsibility for it. Besides, it is a false sense of security to have some one to blame and hardly does you (or your family) any good when you are dead, because your buddy did not come to the rescue.
Personally, I hate limits! Especially artificial ones (which the NDL certainly are). Besides, there are all those reefs out there with no other divers on them, just waiting to be explored. That is how the Coelocanth was discovered…by a diver just exploring where others did not go.

Why Sport Divers should go Technical

2008-01-15T13:45:00.000+02:00

One of the frustrating things about being labelled a technical diver is the image of technical diving as being only for hardcore, extreme exploration. Yet technical diving is something that every sport diver should consider simply so that they can improve their own safety underwater.
Sport divers seem to have the perception that so long as they stay below 40 meters and within no decompression limits, they are safe. Yet when one looks at statistics (such as those published by BSAC http://www.bsac.org/uploads/documents/Diving_Safety/incidents/2007_Annual_Report.pdf) it becomes clear that it is the sport divers and not the technical divers that carry the highest risk. A look at the statistics shows firstly that the majority of the incidents taking place do so below 30 meters. Secondly, the statistics seem to indicate that a lack of basic skill (specifically ascent rate) are to blame.
These trends tend to enforce my personal experience of sport divers (garnered over 15 years, ten of those as instructor). Once sport divers acquire their open water 2/ advanced certification, they tend to think they are invincible and can do any dive… so long as they stay within the no decompression limits. The introduction of dive computers has not assisted, with divers simply strapping on a computer, grabbing a cylinder of air and going where they please.
This attitude was highlighted recently when I heard about an experienced PADI instructor (with no technical qualifications, so limited to 40 meters and using a single tank and air) who was proudly advertising a weekend excursion to Wondergat (one of South Africa’s inland dive sites with a fascinating cavern that starts at 40 meters and extends back about 100 meters to reach a total depth of about 60 meters) where she took not one, but three students to the back of the cave (60 meters and requiring a 100 meter swim with a descent of 30 meters), on air. Because of its depth this dive is a normoxic, Intro cave dive and most definitely not a deep air, advanced diver dive.
Now as a deep air diver myself I can hardly point fingers, except for one thing, my deepest ever deep dive on air was to 65 meters and I never, ever go deeper than 50 meters without weekends of build up. I also never, ever go deep on air without twin sets and staged bail out. Their dive was on single cylinders. They had placed a single bail out cylinder somewhere on the way up. Much good it would have done them if they had needed it. The swim out of the back of the cave is hard, especially if you are panicked, have lost a light and destroyed the visibility. The instructor thought she knew what she was doing because she was an instructor. They all came back, which just enforces their perception that they are brilliant divers and that this is an easy dive, well within their capabilities. But they were lucky. That exact same dive, under exactly the same circumstances (except that the instructor was actually technical trained and experienced) killed himself and his student. The student panicked and ran out of air at the back (they were on singles, it was dark… and deep). The instructor assisted, but they never made the staged bail out and ran out of air on the swim out..
Sport diving is only safe if you do not break the certification limits. If you want to go deeper or stay longer you must have a course such as Advanced Nitrox. If you want to become more self reliant and to reduce your risks on sport divers than you should definitely do an Advanced Nitrox course.
In my next post I will go into the basic skills that you need to safely explore the so called ‘sport’ (40 meters) zone underwater.

Welcome to the Liquid Edge and the World of Technical Diving

2008-01-15T11:33:00.000+02:00

As a diver there is a line that defines you - an edge if you will between where you are and where you are going. This is the liquid edge and is as much about learning new skills, as it is about pushing past your own definition of what you think you can and can not do.
As a diver you probably define your growth by the courses you have taken and the skills you have acquired. Until one day the next course is no longer defined as sport diving, but as technical. Technical courses are not only designed to get you deeper for longer. They are as focused on improving your safety underwater by increasing your understanding of the risks and giving you a tool set that allows you to minimise these. In fact, technical courses should give you a new confidence and attitude toward diving. You may or may not be interested in exploring deeper than 40 meters or in overhead environments like caves and wrecks, but that does not exclude you from integrating technical skills and thinking into your ‘sport’ diving. Technical Diving is about exploring, be it the sea or inland caves. It is about learning new skills. Becoming a technical diver is all of that and more.... because becoming a technical diver is also about exploring your own limits. Limits are choices and the only limits that exist are the one's you believe in!

So welcome to the world of technical diving where choices are limits. Have you chosen yours ?