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http://www.cisatlantic.com/trimix/text/HOGARTH3.TXT
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IN THE BEGINNING...
-------------------
Divers belonging to a Florida based organisation called the Wakulla Karst
Plains Project (WKPP) hold most of the world's cave diving depth/distance
records, including one awesome three kilometre penetration at an average depth
of 87 meters.
Now you might think that the life support equipment needed to survive these
record breaking exposures would be like something from NASA - big, complex and
expensive. Wrong. The WKPP cave diving equipment system is made from
inexpensive
and readily available components. It is slick, light and
streamlined - a model of efficiency and economy. And its applications reach far
beyond the confines of extreme-range mixed-gas cave exploration - it is ideal
for recreational cave and open water technical diving too.
A N D T H E W O R D W A S H O G A R T H
===========================================
Conceived originally by Bill Hogarth Main and refined to a state of Zen-like
simplicity over tens of thousands of dives, the Hogarth system is the
embodiment of the 'less is more' philosophy. Every item in the Hogarth rig has
been considered in relation to every other. The result is a minimalist approach
in which a few carefully chosen components are integrated into a total life
support system. Hogarth is clean, neat, safe and cheap (
).
To a Hogarthian diver anything less than optimal is unacceptable. By contrast,
many divers prefer to mix'n'match equipment on an ad hoc basis. These more
arbitrary configurations are usually described by the term Personal Preference
and include helmets with torches clipped to them, back-up regulator long hose
strapped to the tanks with bungy rubber, technical or jacket style BCs with or
without redundant bladders, primary-light battery packs clipped across the
bottom of the tanks (butt-mounted), and breathing from the short hose.
While Personal Preference may appeal to small 'l' liberals, it is an anathema
to Hogarthian divers who consider it sloppy, ill-conceived and dangerous. They
claim it creates more problems than it solves, and if there is a plan behind
it, it is purely to maximise retail gear sales.
ON A WING AND A BACKPLATE
-------------------------
The Hogarth system is based on a backplate bolted to dual tanks and a single
set of Dive-Rite wings
. Only one set of wings is used. If redundant buoyancy is
required it is provided by the drysuit (trilaminate membrane - not neoprene,
I'll explain why shortly).
The backplate is worn with a single piece of webbing threaded through the plate
to form shoulder loops and waist straps. The waist straps are fastened by a
weight belt quick release buckle. A crotch strap is attached to the bottom of
the backplate and runs forward between the legs to loop onto the waist straps
at the front.
There are just three D-rings on the main webbing, one at each shoulder and one
at the left hip. The D-rings are held in place with weight retainers threaded
onto the webbing. A fourth small D-ring is attached to the crotch strap at the
back. Unlike technical BCs, the Hogarth rig leaves the chest clear and clean.
The webbing stays tight and close to the body. There are no projections to
catch or dangling straps to snag.
No weight belt is worn
. Instead, two manifolded steel
tanks of 12 or more
litres provide negative buoyancy even when empty. If more weight is needed, a
heavy stainless steel backplate is used. If even more weight is required, a
long lead weight (V-weight) is bolted to the backplate between the tanks. By
eliminating the weight belt, the Hogarth system eliminates a source of danger
from accidental release and line entanglement, inefficiency due to extra mass
and drag, and discomfort.
For the same reason, neoprene drysuits are unacceptable
. Weights must be
carried to counteract the neoprene's inherent buoyancy near the surface. At
depth the neoprene compresses (even pre-compressed or crushed neoprene holds
compressible gas bubbles) and loses buoyancy, so the wings must be inflated to
compensate for the weights. Inflated wings produce drag which requires extra
energy to overcome. The extra energy increases gas consumption. Increased gas
consumption limits the diver's range which, in turn, limits the effective range
and safety of the whole team. This cascading series of problems is typical of
Personal Preference equipment and configurations.
LET THERE (ALWAYS) BE GAS
-------------------------
An isolation manifold connects the tanks, enabling a faulty regulator to be
isolated while still giving access to the gas in both tanks. A first stage is
attached to each valve.
The first stage behind the right shoulder feeds:
a) a second stage on a 7 foot hose
b) the wing inflator hose.
The first stage behind the left shoulder feeds
a) a second stage on a normal length hose
b) a drysuit inflator hose
c) a contents gauge.
That's it - the exact Hogarth rig in which (with only the addition of an argon
drysuit inflation bottle and a pee valve) two WKPP divers set the world
cave-diving penetration record of 4.3 kilometres.
WHERE EVERYTHING GOES
---------------------
The cylindrical cave light battery canister has a belt loop on it which slides
on to the right waist strap. The canister is worn as far back as it will go,
right up against the backplate, where it is in the lee of the shoulder and so
creates no drag.
The waist straps are fastened with a weight belt buckle fixed to the extra long
strap on the left side. The webbing is arranged so that when the right waist
strap is threaded through the buckle and pulled tight, the buckle sits all the
way round at the right side of the body, tight against the light canister.
Thus, the buckle not only secures the waist straps, it holds the canister in
place against the backplate.
The free end of the right waist strap should be long enough to reach round to
the centre front where it is held in place by the loop at the end of the crotch
strap.
Stage and/or decompression bottles are clipped off between the D-rings at left
hip and left shoulder. Contents gauge is clipped off to the left hip D-ring.
Reel (and if wreck diving, folded lift bag) is clipped off on the crotch strap
D-ring at the back. Other stuff - jump reels, line cutter, tables, car keys
,
paperback book, deco toys, jelly snakes, waterproof game-boy, etc., - fits into
a flapped pocket sewn and glued to the front
thigh of the drysuit.
The second stage on the short hose is your back-up regulator. It comes over
your right shoulder and is held close beneath your chin by a surgical rubber
loop which goes round your neck.
The second stage on the long hose is your primary. This is the one you breath
from throughout the dive and donate in an emergency. The hose goes down the
side of the right
tank
behind the wing to waist level, then it turns forward,
passes between your body and the bottom of the light canister, comes diagonally
up across your chest, over your left shoulder, around the back of your neck and
the reg goes into your mouth. A clip on the hose next to the regulator allows
you to 'park' it on the right shoulder D-ring when not in use. When gearing up,
the long hose is the last thing you position, so it ends up on top of everything
else.
WHAT DOES IT ALL MEAN?
----------------------
All Hogarthian dive team members know where their partner's gear is in a
black-out or a silt-out. There is no reg-swapping during the dive (as is
necessary with independent doubles). The long-hose primary remains in the mouth
until a team-member needs it in an emergency. You hand it off to the out-of-air
diver, duck your head to release the hose, and immediately he/she has 4 - 5 ft
of hose. You then reach down and flick the hose from beneath the light canister
and she/he now has the whole 7 ft.
The reason the out-of-air diver gets the reg from your mouth is because a) you
both know it works - you were just breathing from it, and b) in a silt out,
he/she may not be able to locate your secondary regulator by touch, but she/he
can always find your head by touch, and thus, find the primary reg in your
mouth. See? Everything has a reason.
The reason for the long hose is that when two divers wearing doubles are
sharing gas in passageway, a short hose makes progress out of there next to
impossible.
Your back-up regulator is always tight up under your chin, You can find it and
lift it into your mouth instantly. Some people can actually duck their heads
and grab it with their mouth, hands-free.
NOT JUST WHAT BUT HOW
---------------------
1. Strict team diving - your buddy is part of the Hogarth system
2. Strict gas management rules (thirds or better)
3. One depth gauge and
one timer
per diver (Uwatec digital depth gauge and bottom timer is good) -
your partner's gauges are your back-ups
.
THE ART OF BREATHING
--------------------
To improve reliability and performance it is common to put first stages from
one manufacturer with second stages from another. In the US Poseidon
Odin and
Scubapro MK20 first stages with Scubapro G250 or Apeks/Zeagle/Beuchat VX-10
second stages are used for bottom gas. In Europe the MK20/G250 combination is
favoured, along with Apeks T50D firsts and seconds. In Australia, Sea Hornet
Command Air firsts and seconds predominate.
Stage bottle second stages needn't be high-performance
. But they should be
reliable, dry breathers and, most importantly, not free flow. Balanced piston
first stages are usually used with lower performance second stages. On deco
cylinders you'll appreciate easy-breathing regulators, especially on long
hangs. High flow rates aren't necessary because these regs are used shallow and
at low work-rates. In the US, piston first stages like the Scubapro MK20 or
MK10+ are used with G250 second stages. In Europe the MK20/G250 combination and
the Apex T50D first and second are favoured. In Australia we tend towards
Command Air firsts with Oceanic Alpha
seconds.
All second stages should allow you to unscrew the cover underwater, pull out
the diaphragm, swish them around to clean any muck out of them, loosen a
sticking mechanism, then put them back together. Again, there's a reason for
everything.
LOOK MA, NO COMPUTER
--------------------
Dive computers are not used for mixed gas diving in the Hogarthian system.
Instead, software like Decom (imperial) or ANDI Dive Planner (metric), based on
proven Buehlmann
algorithms, is used to plan your dives beforehand. You then
prepare tables and contingencies for the depth you're diving and the gas you're
carrying. The tables are written out or printed and laminated. Two copies are
carried. Using this software makes you think through your dives beforehand. You
can model alternative profiles and gas mixes
. And you begin to see patterns
emerge. After a while, you get to know the sort of deco shapes and times to
expect for different dives.
Many Hogarthian divers modify their tables over a series of dives to
incorporate new findings in hyperbaric medicine and bubble mechanics
. The
modifications generally include the addition of deep stops.
Obviously, no one person can think of everything, so Hogarthian divers tend to
distil the wisdom of many and only choose the best, the proven and the most
justifiable - which is why the Hogarthian system seems fairly well
standardised. For those people who have any "what abouts..." as in "what about
my 'bondage wings/technical BC?..." "what about my aluminium tanks?
..." or
"what about my neoprene drysuit?..." you should remember that the people who
put together the Hogarthian system have had the opportunity to try almost every
piece of diving equipment in existence. They have dived it and either integrated
it into the Hogarthian system or rejected it as deficient. There is Hogarth and
then there is Second Best.
If you would like to know more about the Hogarthian system, internet access is
a must. If you don't have access, find someone who does and ask them to
download and print the contents of these sites for you:
http://www.infinet.com/~toddl/caverig/
http://www.crl.com./~jbentley/cave.html
http://www.wkpp.org
http://www.infinet.com/~toddl/caverig/jjpaper.html
the "Doing It Right" video:
http://www.wkpp.org/videos.html
AND THE LAST SHALL BE FIRST
---------------------------
Finally, the First Rule of Hogarthian diving is possibly the most important
piece of wisdom in the diving world, and is something we should all apply to
all of our diving. It is, simply, 'Don't dive with strokes.'
The term 'stroke' refers to someone who, knowing there is a better system,
chooses to dive in a less than optimal way. It applies to those instructors who
encourage students (who know no better) to exercise Personal Preference
, in
order to sell more equipment
; it applies to those who don't plan their dives;
those who dive beyond their abilities; who dive deep on air
; who take
unnecessary risks; who do big dives using unfamiliar gear; who's only reason
for diving is depth.
Diving with strokes moves us into an area where our safety is no longer in our
own hands. Strokes are sometimes highly 'qualified'.
Often they seem very
confident - usually because they have no concept of the danger they are getting
themselves, and you, into. Strokes appeal to your sense of adventure while
pretending to adhere to some standard of common sense. In groups, strokes are
capable of exerting extreme peer pressure. And in case you believe you are
immune to strokism, just remember that two of the leading diving explorers of
our times, Rob Palmer and Rob Parker, recently succumbed to peer pressure and
died on deep-air dives. So whatever else you do, remember the penultimate rule
of Hogarthian diving and apply it with no exceptions: Don't dive with strokes.
They're out there. And they will kill you.
billy williams