Wednesday, February 27, 2008

Open or Closed Manifold ?

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.

Wednesday, February 20, 2008

What is a Hogarthian Equipment Configuration ?

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!

- 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.

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.

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).

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.

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.

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 :)

Monday, February 11, 2008

Solo vs Buddy or should it be Self Reliance ?

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)

Tuesday, February 5, 2008

Thank Heaven for Support Divers

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.