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 :)