The Evolution of DIR Principles
By Jarrod Jablonski
Great Individuals Created Cave Diving, But It Is Good Equipment That
Enables Them
Few aspects of cave diving engender biased
convictions like the topic of equipment configuration. Different people
diving in different environments often reach very different conclusions.
This tremendous diversity often surprises the new cave diver who usually
expects that there will be a consensus among the "professionals."
In fact, this diversity has been known to initiate rather energetic disagreements
and while cave diving has undergone some significant changes during the
last roughly 50 years of its evolution, few aspects of the sport remain
more hotly contested than gear configuration. Perhaps because one's equipment
is often a rather personal choice and people are prone to take offense
when their decisions are challenged.
Regardless of the reasons, dozens of styles
have been marched out to center stage and purported to be the most effective,
the safest, the easiest, the cheapest, or lately, even the most "technical."
Some people have casually recommended one style over another, others have
adamantly insisted upon their configuration, while still others advocate
that one just do what feels good. How can one sport support such a variety
of opinions and, perhaps more importantly, how is a diver to dim the clamor
of opinions in order to make a sound and reasonable decision?
The most sensible way to make any educated
decision is to gather information and evaluate which of the available
options best satisfies your particular needs. A diver will be able
to swim themselves into a cave using almost any style of gear configuration.
Many an open water diver has returned unscathed from a poorly chosen
venture into the depths of our cave systems; based upon their safe
return (this time), their consensus is to continue to breathe the
short hose because they find it to be "more comfortable."
The long house is usually "stuffed" during the equipment
assembly portion of the dive. The hose must be run so that deployment
allows the full length of the hose to be utilized. During the pre-dive
drills so common in the cave community, the divers practice out-of-air
drills and acquaint each other with the location and deployment
method to be used in an emergency. Following the exercise, most
divers have their dive buddy replace their hose back in the original
position. Divers must therefore be wary that because they were unable
to configure this vital portion of their equipment themselves, it
may be done differently or even wrong. Some divers are able to "stuff"
their own hose while in the water, but they remain a minority despite
the potential risk.
|
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Bad Form: Primary hose is both stuffed and
routed under the diver's arm, with butt-mounted primary light and
tank-mounted reserve lights |
Opinion on where and how to secure the second
stage of the long hose varies among divers, yet most agree that the triangle
formed by the chin to the nipples is the best region.
Some prefer to use a retaining device like
those often employed by open water divers to secure their octopus, while
still others prefer to secure the second stage under the chin with a surgical
band running around the neck. While still others prefer to secure the
second stage under the chin with a surgical band running around the neck.
This location does seem to limit the chance of having the regulator pulled
free as it is away from the frequently abraded area of the chest and also
is more easily retrieved when the chest is cluttered with equipment.
Occasionally, divers will secure the long
hose in a retaining band, breathing off its regulator and donating it
in an emergency. The short hose second stage would then be secured in
one of the manners discussed above, usually below the chin. While a few
divers utilize this style it is somewhat uncommon. Most divers breathing
the long hose configure in the manner discussed below.
Evolution of the Hogarthian Style
The concept of Hogarthian diving is often misunderstood, sometimes misrepresented
and occasionally complicated unnecessarily. In the simplest of terms, the
Hogarthian concept embodies simplicity and functionality. At the heart of
this concept is the conviction of minimalism. Items that are superfluous
should not be part of one's diving attire- when in doubt leave it at home.
On a deeper level the Hogarthian configuration
is more than a style it is a system or perhaps more pointedly a process.
Every aspect of the true Hogarthian dress is an integrated part of a life
support system. Confusion sometimes arises when people try to review or
adopt a single part of an integrated process. This system must be looked
at and evaluated as a whole where it most effective. Certainly divers
may choose to adopt isolated aspects of the system but adopting one aspect
of an integrated unit cannot be considered diving Hogarthian.
The Hogarthian configuration is named after
William Hogarth Main, a cave explorer of significant accomplishment. The
individual components that resulted in this system grew from many divers
all striving to maintain the original vision of clean task-oriented diving
style. In truth, cave explorer Sheck Exley was one of the first cave divers
to promote using the longer 7' octopus hose as a primary, donating air
from the regulator in one's mouth. Yet, it was certainly Bill Main and
Bill Gavin's early years of diving that defined the Hogarthian view of
diving. There efforts not only resulted in the birth of the Hogarthian
system but coupled with Parker Turner and Lamar English proved to be the
genesis of the highly successful Woodville Karst Plain Project (WKPP).
Later, WKPP members George Irvine, Jarrod
Jablonski, Casey Mckinlay, Brent Scarabin, Rick Sankey and a cast of indispensable
members would continue refining the Hogarthian system, using it to establish
a new age in cave exploration. From its early years the Hogarthian system
was designed and refined by explorers focused exclusively on developing
a user-oriented diving system. Over the years the efforts of the Woodville
Karst Plain have grown into a membership of more than 80 individuals and
pioneered a new age in cave research, exploration, and education. The
Hogarthian concept continues to play a central role in the efforts of
both the WKPP and an international host of leading explorers.
Breathing The Long Hose
Despite its growing popularity, many divers
remain opposed to donating the regulator from their mouth. The following
discussion reviews the most common resistance to donating the long hose
from the mouth.
"The last thing I want to do in an out of
air situation is give up my primary regulator"
This concern does not really seem to be a
rational fear. It is likely that a diver incapable of removing the regulator
from his or her mouth for five to ten seconds is not skilled or practiced
enough to be in an overhead environment. One may question this divers
ability handle an out of air situation in which the out of air diver chooses
the regulator in their mouth despite their best intentions. A diver with
this degree of concern over the regulator in their mouth may find it quite
a challenge to even deal with the very real possibility of an accidentally
dislodged regulator.
By donating the long hose regulator from the
mouth in an out of air situation one guarantees that the person most in
need of a clean fully functioning regulator is going to get it. If you
pass any other regulator to an out of air diver it is possible that the
regulator received may contain contaminants that will be impossible for
the stressed diver to manage. In essence, what you will have done is to
place the last straw on the camel's back, creating the last problem your
dive buddy can manage. The advantage of donating your long hose primary
is that you are always ready for this very real possibility. You are,
in essence, always prepared for any eventuality rather than maintaining
a fixed picture of how things should operate. Emergencies have an annoying
habit of not going as planned and the Hogarthian system strives to remain
prepared to manage a variety of out of air scenarios.
"I don't want to breathe my long hose, I want to
have the best performance regulator in my mouth and the long hose decreases
this performance"
With literally thousands of deep exploration
dives accomplished by divers breathing the long hose, the performance
argument seems rather a moot point. Yet, if one were to insist that the
reduction of performance is unmanageable, it seems like a poor solution
to leave the stressed, out of air diver gasping for air on this lower
performance regulator so you can have a more relaxed dive. Your best performance
regulator must be on your long hose and if its performance is unacceptable
in a relaxed situation then it is certainly inappropriate to suggest that
the your stressed dive buddy is better prepared for this increased resistance.
The one thing to be clear on is that if the regulator you try to provide
to an out of air diver is in any way substandard, you will be giving up
the regulator in your mouth and your ability to handle that situation
may make the all the difference.
"I just don't want to deal with that hose on the
second stage in my mouth"
Any skill worth learning usually takes refinement.
The long hose may at times seem uncomfortable to some people, but regardless
of your storage location, you have to deal with that hose. When you tuck
a long hose into some surgical tubing you feel that it is forgotten and
indeed for some it is, but what happens when it pulls free or is not set
just right? If you rely on your buddy to arrange this hose for you, what
guarantee do you have that it is to your liking or even correctly placed?
In a sport that preaches self-sufficiency, does it seem logical to configure
your equipment in a way that forces dependence on your dive buddy?
THE SYSTEM
No review of the Hogarthian style is complete without a discussion of the
system itself. It is not merely the streamlined nature of their equipment
nor the use of the long hose that sets the Hogarthian diver apart, it is
the way the pieces are carefully arranged to create a harmonious system.
Your equipment must function cohesively and be configured so as to provide
you with the greatest support- it is after all life support equipment. For
example, let's assume that you have made the commitment to breathing the
long hose. That decision, in and of itself must not be the end to your deliberation.
In fact, it is really only the beginning. Where and how you store the balance
of this length of hose and indeed how long it is are at least as crucial
as your decision to use it as a primary.
Most practitioners of this style have opted
for the 7' length (nine is ridiculous and dangerous in most situations
and 5' is precariously short in restrictive passage) and then run it down
the right side of their body, under a hip mounted light canister, across
the chest and around the neck into the mouth. Do not try and wrap this
hose around your neck multiple times (this may be quite dangerous) as
its deployment will be time consuming and awkward. This system is ideal
in that it allows nearly seven feet of house to instantly be available
and the remaining two to be deployed with a quick flick of the hand. In
addition, the diver can easily return the long hose to its original position.
While some styles require another divers assistance, this system allows
complete self-sufficiency. Many people argue that this ability to replace
your own hose is unnecessary as your deployment occurs only in times of
emergency and would therefore eliminate the need to return it to the original
position.
In fact, most situations that require the
deployment of one's long hose are relatively temporary and regardless
of the style chosen every diver must develop a way to manage a deployed
hose. Thankfully, a complete loss of air is highly unusual. The high degree
of reliability found in modern equipment, coupled with the redundancy
of equipment used in overhead diving, severely reduces the likelihood
of a diver ever experiencing a true loss of air. However, it is quite
possible that one could experience a temporary loss of air for a number
of reasons including: the rolling shut of a valve, the loss or failure
of a regulator, the inadvertent closure of an isolator valve. All of these
scenarios still leave the diver with an air supply yet several qualified
individuals have drowned with significant air available so it is obvious
that even the most temporary loss of air could be fatal.
Clearly even a temporary loss of air is a
serious consideration, yet these situations are relatively temporary and
when dealt with effectively they should pose no serious threat to the
diver. Obviously the first line of defense in the temporary interruption
of air is for the diver to solve the problem themselves. In most cases
the diver need merely switch to their reserve regulator. Unfortunately
some divers are not adequately prepared for this loss of air and may be
caught unaware. Occasionally a diver experiencing an interruption in air
supply will go to a dive buddy for air despite the air available on their
own backs. This decision may be rather risky depending largely on the
distance separating the divers but also upon their ability to manage the
situation. While it would be preferable to solve the problem without the
need for sharing air this may at times become a necessary or at least
suitable decision.
Often these air sharing episodes are relatively
short in duration and the problem is solved and the diver is returned
to their own air supply. Following this transition the air donor must
manage the no-longer needed long hose. To be sure, one has several choices
when placed in this situation. One may simply try to get a dive buddy
to restore their hose though in some restrictive or low visibility situations
this may be difficult. One may also loop the hose and/or clip the second
stage off to a D-ring. Regardless of one's choice it is important to try
and retain this regulator in a manner that will reduce the likelihood
of an entanglement that could create further task loading. Historically,
diving accidents start as a series of smaller problems culminating in
one apparently unlovable situation. The key to safely managing a small
problem is to prevent it from escalating into a large situation. It is
most important that the diver have a predetermined plan to manage issues
like a deployed and no longer needed long hose. Certainly the ability
to reconfigure your own long hose, regardless of your method, is highly
beneficial.
Equipment Configuration
The debate over equipment goes well beyond the use of the long hose regulator
and divers tend to vary in their solution to the many trials and tribulations
of equipment placement. The new cave diver is often surprised at the energy
expended over the most seemingly minor decisions. Some divers appear fanatical
in their struggle to refine their equipment placement. The only real consensus
within the cave community maintains that divers entering an overhead environment
should "streamline" their equipment. Exactly what is meant by
that term seems to vary greatly, yet the rationale is that anything hanging
free or protruding from the diver's body increases one's risk of becoming
entangled in the guideline. Admittedly, some environments contain even more
risk of entanglement than that found within most cave systems. For example,
wrecks often contain all manner of entanglement including such hazards as
disintegrating cable which may be more dangerous than cave line.
Regardless of one's environment, a truly streamlined
diver is safer and more efficient. Items that are attached to the diver
must be secured to limit or prevent the risk of entanglement. Nearly all
divers preparing for overhead encounters talk about streamlining but their
dedication to this concept varies greatly. Divers that discuss streamlining
and then allow backup lights to swing freely from their tank seem to be
missing the point. All equipment must be secured so as to truly limit
the likelihood that the diver will become entangled, yet a properly configured
diver should strive for more than this one aspect. For example, hoses
should not only be configured to avoid entanglement but also to simplify
one's access to their valves in the event that an emergency shut down
becomes necessary.
Many divers appreciate that certain extraordinary
dives may require a degree of refinement simply unnecessary for the average
diver. Yet in much the same way space travel is merely a distant dream
for the majority, the advances gained from this pursuit are abundant.
How much of this refinement is reasonable or more importantly helpful?
One's attention to detail should at least be proportional to the type
of dives done, but that strict attention to detail couldn't hurt. If all
your dives focus on the main line and your penetrations are modest, perhaps
your idea of strict attention would be different. If your dives begin
to incorporate stage diving and longer penetrations then undoubtedly you
should exercise a complimentary form of attention. In general, always
be aware that you should look at the entire package as it functions together.
Your equipment should be a cohesive unit that facilitates your dives and
not a haphazard collection of available items.
Too many divers today seem under the impression
that more is always better. In cave diving what is needed is better; that
which is not needed is a detriment. Equipment choice like most things
is a cost vs. benefit analysis in which one must weigh the potential risk
against the perceived benefit. The difficult part and in fact the thing
that really defines a safe and effective diver is their ability to accurately
evaluate the benefit while candidly weighing the acceptable risk.
From Head to Toe
The mask is certainly one of the most vital
portions of the cave divers equipment. The importance of one's mask goes
well beyond the obvious desire to see in your environment. The mask should
fit comfortably, be low volume to reduce drag, and be reliable. The diver
should be careful that the lenses of the mask are not too easily removed
as they may become dislodged accidentally. The strap must be secure and
resilient so as to limit the risk of dislodging the mask or breaking the
strap. The after market straps that substitute a neoprene style strap
are usually quite comfortable and seem to be nearly unbreakable.
Some divers swear by the need for an extra
mask yet many divers opt not to carry a spare mask. Masks are generally
quite reliable and their failure unlikely. However, given the potential
danger of losing one's mask it is worth consideration. While placing the
mask one must be wary that it will not be damaged and that it is easily
accessed. To that end, many people put the mask on a light canister, in
a spare pouch on the belt, on their thigh, around the neck or in a suit
pocket. The spare mask should also be the as small as possible while still
providing a comfortable seal.
The diver should also be aware that when a
spare mask is removed from any of the above locations and placed on one's
head it will immediately begin to fog. Certainly, one could treat it with
defogging agents prior to each dive; however, this is not only rarely
done but somewhat ineffective. Most people disregard this fogging but
it will frequently be very disconcerting. In addition, most people leave
this spare affixed and rarely check its viability. One solution to all
these problems is to pre-treat the mask with a concentrated defogging
agent and place it in a water tight bag and then in a pouch. If the diver
uses a pocket mounted to the side of the leg the belt remains uncluttered.
Of course the mask must still be checked on a regular basis to insure
its ability to function.
Dive Lights
Dive lights are an essential portion of your equipment yet more is again
not always better. One primary and two backup lights should be fine for
most situations. Unless you intentionally dive faulty equipment or ignore
common maintenance the likelihood of a triple light failure is statistically
insignificant. Divers that carry numerous backup lights are weighting themselves
down without good cause. The most efficient solution to one's lighting needs
is to focus on quality not quantity. As you begin to carry unnecessary equipment
you often create more problems than you solve. The primary light must have
a burn time at least equal to one's bottom time while the two smaller backup
lights should burn twice the planned bottom time. The fear over exiting
with the inconvenience of a small reserve light has encouraged some divers
to carry two primary lights. This is usually fairly prohibitive and generally
unnecessary. Quality lights rarely fail and their failure is typically a
bulb which will almost always fail when the light is activated at the onset
of the dive. Given the unlikely nature of a light failure an extra primary
light attempts to solve a nonexistent problem and instead forces the diver
to deal with the very real problem of excess drag, extra weight, line entanglement
and task loading.
The location of one's lights is a very important
aspect of equipment configuration second only to the placement of the
air delivery system. People commonly store the primary light on the hip,
hanging from the bottom of the tanks, or occasionally mounted to the side
of the cylinders. People that prefer the light hanging from the bottom
of the tanks (often called butt mounted) claim that the light is free
from entanglement and leaves the body less cluttered and more streamlined.
This appears at first glance to be a reasonable conclusion and admittedly
there are those that function well within this system. Many of the disadvantages
to this system appear small but are not inconsequential.
One of the most fundamental rules in overhead
diving maintains that the diver must preserve a feet up attitude to reduces
the risk of disturbing sediments. Therefore, it seems contradictory to
place a canister below the tanks were they will tend to drag the legs
down. Of course, one could dive some of the nearly neutral lights on the
market and reduce this impact but if the canister leaks the result will
be a significantly heavier light now creating a rather inconvenient buoyancy
problem. In the wrong place the resulting feet down posture could be a
problem and given that the configuration prevents easy removal of the
light the diver has no choice but to continue the struggle.
The inconvenience of removing and replacing
a light located below the tanks should not be ignored. Some people are
fairly adept at the procedure, yet it is nearly always a bit of a trick
to secure the light properly. The greatest disadvantage to this effort
occurs when the diver experiences a problem with the light such as a flooded
canister, a line entanglement, or a failure of the attachment hardware.
The butt mounted light is difficult to reach and therefore the above situations
may create problems the diver cannot manage adequately. Smaller, yet other
realistic criticisms of butt mounted lights include the extra length of
light cord necessary and the elimination of a the crotch strap as an ideal
storage location.
A longer light cord increases the difficulty
of maintaining a clean profile as one must maintain an even more troublesome
length of cord which can easily snag on rock protrusions. The last notable
disadvantage to the butt mounted light is the clutter below one's tanks.
While many argue that the area below the tanks is a wasted area and therefore
perfect for the primary light others have found this region to be an excellent
area for all manner of equipment storage. A d-ring attached high on the
crotch strap provides ample storage for items like reels and lift bags.
Reserve scooters are also easily towed from this area. In addition, divers
with diver propulsion vehicles (DPV's) should appreciate the amazing efficiency
possible when towing a diver holding onto a crotch strap. The speed and
efficiency gained by towing a stranded diver from the cave is remarkable
and may well make enough difference to allow an otherwise questionable
exit.
Mounting one's light to the tanks presents
some very simple disadvantages. Very few individuals opt for this method
as it is an awkward, high profile, low efficiency system. A light mounted
on one's tanks will create unnecessary drag, increase the risk of line
entanglements, and eliminate the possibility of underwater removal. Single
tank divers are often limited by the equipment they wear and many buoyancy
compensators reduce the locations available for mounting a primary light.
Occasionally these divers will mount the light on their tank with a fair
degree of success. However, most people using the large style canister
light are diving double tanks and therefore have more flexibility, and
usually avoid mounting the light on the tank.
Many of cave diving's most prolific explorers
have relied on the hip mounted canister, yet the general community has
only recently began to embrace its advantages. Some people complain that
a canister on one's hip gets in their way and that it does not allow for
the same streamlining that a butt mounted light provides. The opponents
of hip mounted lights raise a couple good issues and like many controversies
there is a measure of truth to their assertions. However, the biggest
issue revolves around two misconceptions. First, the claim that the hip
mounted light is less streamlined is only partially true. Many people
having problems with this style mistakenly allow the light to hang too
far down on the waistband. The light must be close to the backplate and
under the shoulder. This location keeps it from interfering with one's
kicking and places it in the same water column already broken by the shoulder.
In this location the light is quite streamlined and will not have a negative
impact on the divers speed in the water.
The second misconception involves wearing
stage bottles. Some people believe that a diver with a hip mounted light
cannot efficiently wear multiple stage bottles. Again one should look
at the explorers in the community to judge the validity of that concern.
Most of the active exploration done in North America is done by divers
with hip mounted canisters. These divers often carry two, three, four
or more stage bottles and manage quite effectively. Most of these divers
place multiple bottles on one side of the body. A double stage dive would
be conducted with the two bottles on the left side of the body, opposite
the light canister. This system allows a diver more flexibility as one
arm is unencumbered. The diver may more easily pilot a scooter and often
finds that they can work through smaller areas with stage bottles intact.
It is common to place the first bottle to be dropped on the outside where
it is more easily reached. If neither bottle is to be dropped the richer
mixture is usually placed on the inside or closer to the hip as it is
the last to be used. If another bottle is needed one can clip another
bottle to a small d-ring on the light canister.
Reserve Lights
Reserve or backup lights are undoubtedly an important portion of the overhead
diver's equipment. These lights must be reliable, stream lined, and conveniently
located. As mentioned each must have sufficient burn time to allow a diver
to manage even a delayed exit. The common recommendation is for each light
to have a burn time at least equal to the expected bottom time. Following
a primary light failure the diver must switch to the reserve light and initiate
an exit. The time spent on a reserve light should not be much greater than
half the divers bottom time, however, a reserve light should provide more
time in the event of a delayed exit. While the primary light should contain
rechargeable batteries the reserve lights must contain disposable batteries.
These batteries have a more reliable burn time and will provide consistent
and predictable results. The reserve lights are rarely used but when used
they must be reliable.
These lights could be stored in several places
and some people advocate that they be secured to the tank. If this location
is chosen one must clip the lights to a d-ring on the tank and tuck the
light into some type of restrictive band like surgical tubing. Far too
many people leave the lights dangle and yet claim to be streamlined. Leaving
the lights merely hanging form the tank is an unacceptable practice for
the efficient overhead diver. Mounting one's lights on the tank does keep
them out of the way yet some people consider they are kept too far out
of the way. This location inhibits easy access, limits one's ability to
see if the light has been knocked on and forces one to remove the light
prior to turning it on.
When placed on one's harness below the arms reserve lights tuck neatly
out of the way and are essentially snag free. A diver experiencing a primary
light failure with no other divers immediately around will find that a
light which can be turned on prior to its removal is rather beneficial.
If dropped this light can now be easily retrieved. Also, one can activate
the reserve light and leave it affixed while managing any other equipment
issues. Lights located on the harness below the arms are easier to remove,
easier to activate, easier to replace and do not require that one add
additional equipment like clamps and d-rings to the tank.
Manifolds
A manifold is a device that combines the supply of two, usually back mounted
cylinders. The manifold allows one to breathe off two cylinders at the same
time. All of the newer manifolds allow the diver to place two redundant
regulators on their twin tanks and to shut off either one while maintaining
access to both cylinders. In this way a regulator failure does not limit
the divers use of any air. The valve controlling the failed regulator is
simply shut down and allowing the diver to access all the air via the second
regulator. Many of the newer manifolds also allow the diver to interrupt
the flow of air between the cylinders.
Manifold failure is often considered to be
one of the worst situations an overhead diver could experience. A catastrophic
manifold failure could leave the diver without air in a matter of minutes.
Obviously such a failure is cause for concern. However, our concern is
usually not very justified as failures especially the catastrophic type
are very, very rare. The alert diver has several different options in
the quest to avoid this unlikely scenario. One could choose to dive without
a manifold and altogether eliminate the problem. However, manifolds seem
to be the best method to manage one's air supply as they always allow
access to both tanks and require no taxing gas management.
Two reasonable exceptions are solo diving
and side mount. In solo diving the diver is without a dive buddy and therefore
a catastrophic failure of their gas supply would be fatal. Some solo divers
use a manifold and carry a spare cylinder or "buddy" bottle.
This tank is usually of moderate size (roughly 80ft³) and provides
a redundant supply of air for the exit. Independent valves require that
the diver pay stricter attention to the one third air rule by using one
cylinder for one third of its volume and switching to the second cylinder
to continue the penetration. Upon exhausting the second third from tank
two the diver must began the exit, switching back to the first tank after
another third is used. Any variation of this system could prove fatal
in an equipment failure as the diver would lose access to the air in that
cylinder and may have an insufficient supply for an exit. It requires
great care and superior gas management capabilities to effectively monitor
independent cylinders and experience has shown that most people do not
posses the necessary management skills.
In researching the manifold controversy the
author was unable to discover one event in which a manifold failed catastrophically.
It seems a poor trade indeed to exchange the very low probability of a
manifold failure for the very high probability that one will on occasion
bungle the gas management. Most divers that support independent use admit
that even they succumb to the use of a manifold in deeper dives as the
increased consumption further increase the likelihood of a miscalculation.
Obviously side mount divers and to a lesser extent solo divers fulfill
a very specific need with independent valves. However, if one is not pursuing
these activities then it makes little sense to configure as if you are.
PROTECTING THE AIR SUPPLY
Inverting The Tanks
Many new cave divers are struck by the apparent foolishness of mounting
the tanks so as to expose the manifold. Many a new diver has asserted
how much more secure the manifold would remain were the tanks inverted.
Alas, that too met an early death. Inverted tanks require all custom length
hoses to reach the now greater distance. These hoses are inconvenient
to route and manage. Perhaps even more compelling is the difficulty in
donning the system for if the manifold is on the bottom then special devices
must hold the tanks while they are being put on. In short, avoid the time
and energy and resist this temptation.
Cages
Cages or other protective devices over the manifold (such as "cobra
guards") tend to be somewhat controversial topics. Supporters maintain
that the manifold must be protected from the abuse of collision. The cages
provide ample security and are therefore, the argument goes, indispensable.
Most opponents are not really against the thing they purport to accomplish
but challenge their "success." If we hit the ceiling on a regular
basis and conclude that a cage is the correct solution perhaps our logic
is flawed or at least questionable. Perhaps frequent impact with the ceiling
should encourage us to slow down a bit and improve our technique. We should
be wary of substitutions to becoming a better cave diver. OK, so everyone
hits the ceiling on occasion but how hard and at what risk is your manifold.
While swimming your velocity is minimal and the risk somewhat inconsequential.
Perhaps the diver on a propulsion vehicle reaches a velocity
that demands our concern. After all, it seems that even the
relatively minor risk incurred justifies protection. The diver
has a variety of choices yet all essentially boil down to two
very similar styles. One of these options place a large dome
style cage over the manifold. This dome appears to be solid
protection but also has an annoying habit of wedging its owner
in small places. Given the likelihood of a manifold failure
most divers would much rather go cageless and remain flexible
in smaller areas. As one long time prominent cave instructor
relayed, "I thought cages were the way to go until I wedged
myself in a tight passage at over 3000' of penetration. I thought
for sure the end was near and upon escaping my first action
was to remove the offending cage." The diver may also choose
the smaller more streamlined version of the cage which substitutes
curved metal guards above your regulators. These seem to be
a panacea if ever there were one. Two people on two separate
occasions were able to break their din regulators off at the
manifold despite the presence of these protective devices. If,
in fact, these devices are limited in their ability to accomplish
what they were designed for than their large line catching profile
seems to be far more a risk than a benefit. Again the emphasis
should be placed on improving one's technique. The manifold
is a highly reliable piece of equipment that will provide even
the most abusive cave diver with years of stalwart reliability.
Isolators
Isolators are nifty little inventions that respond to our desire
for the cake after it was eaten. They are an excellent idea
in theory, and in practice probably fairly decent. As long as
one maintains an awareness of their strengths and weaknesses
they remain effective pieces of equipment. They are, however,
not necessarily the saving grace everyone has you believe. First,
while they may provide a redundant option to isolate your cylinders,
they are also another valve and just as likely to fail as the
one you are circumventing. Be aware that due to the nature of
their construction failure of your isolator will only allow
one cylinder to be isolated thus protecting only a finite amount
of your available gas. Furthermore, one must always guard against
the common occurrence of valves that are inadvertently turned
off during filling or safety drills.
The experienced diver can make use of the isolator to add
one more line of defense against the loss of an air supply.
However, all divers must be aware that a closed isolator could
create problems. If the Isolator is closed prior to filling
only one of the diver's tanks would be filled. If the tank
filled is the one hooked to the pressure gauge the diver may
mistakenly believe their tanks are filled. The symptoms of
this error depend upon which tank the pressure gauge is attached
and which tank the diver is breathing from. If the gauge and
regulator are on the same tank the diver will should notice
a more rapid depletion of their air supply. If the gauge and
regulator in use are on different tanks the gauge will continue
to read the same pressure as one tank is depleted. Divers
have breathed this one tank dry and mistakenly believed they
were out of air.
Generally, these scenarios should merely result in a shortened dive but
the wrong set of circumstances could render this rather dangerous. In
addition, the isolator could be mistakenly shut off by a "buddy"
during the pre-dive safety checks. The diver should experience the same
symptoms discussed above and the aware diver will notice either the unusually
rapid depletion of air or the strange permanence of the air supply. Of
course, leaving your isolator open, remaining aware of your isolator before
and after an air fill and checking it yourself immediately prior to entering
the cave should eliminate these problems and allow the valve to work to
your advantage rather than to your disadvantage.
Knobs
It is shocking how few divers pay any attention to the type of knobs
found on their manifold. Most people seem assume that the manufacturer
has their best interest in mind and would selfishly protect their safety,
just like politicians. Rubber knobs tend to be the best choice. They are
durable, shock absorbent, shatter proof, and easy to turn. Their only
downfall is that if you have a manifold that has one post shut down upon
contact with the ceiling then you must be concerned with the ease with
which these valves turn. The highly resilient rubber Sherwood knobs will
roll more easily then any other knob, yet they are also the least likely
to fail. In addition, they actually appear to absorb some of the shock
of the collision rendering it less damaging. The alert diver merely needs
to make note of the shutdown risk and check the valve following any contact
(a wise habit to develop regardless of the knobs used). Plastic knobs
do turn less easily but are dangerous because they can shatter, leaving
you with nothing to turn on or off. The metal knobs attempt to solve this
and the auto shut off problem yet fall a little short because they can
bend upon impact and be rendered useless.
Tanks
The wide variety of tanks currently available provide the diver with
numerous acceptable choices. Most cave divers prefer the larger volume
lower pressure steel cylinders made by manufacturers like Pressed Steel
and Faber. These tanks generally have a working pressure of 2,640psi.
Many wreck divers still prefer the high pressure Genesis tanks (3,500psi)
but this trend seems to be changing. The lower pressure tanks do not mandate
high pressure to achieve a reasonable air supply but allow for higher
volumes when necessary. Overpressurizing these tanks, for good or bad,
has been a common practice in the cave community for more than two decades.
The Genesis tanks are manufactured under a more precise system and the
manufacturer warns that overpumping would be dangerous.
The tank one chooses should depend on your size, your
needs and your available funds. Do the cave and yourself
a favor and really evaluate your needs. Most people will
find that 95ft³ tanks are sufficient. These tanks
are reasonably light and fairly priced. However, for longer
dives or larger people 104's are a popular choice with
the larger 121ft³ also gaining popularity. One should
also be aware of the manner in which a tank was galvanized.
Some manufactures spray galvanize their tanks which does
not always provide a consistent coat leaving them more
prone to rust. Other manufactures "hot dip galvanize"
their tanks creating a more even coat that significantly
reduces the risk of rusting. Dolphin tanks and Press Steel
tanks are the most popular "hot dip" tanks on
the market.
The weight of the tanks, both full and empty, remains
an important consideration for divers in all environments.
The tanks must remain negative enough to prevent the diver
from becoming positive during the dive. Some tanks are
fine when full but the depletion of air leaves them too
light to provide ample weight. One must insure that even
empty tanks will not cause a rise to the surface. If necessary
extra weight should be added to prevent the diver from
floating. Indeed an emergency air sharing episode that
depleted most or all of the divers air could cause them
to float to the surface unintentionally, ignoring hours
of decompression. One may offset this problem with a conventional
weight belt or even more preferably with weight placed
behind the backplate where it will be completely out of
the way. Most divers in wet suits and fresh water need
no additional weight, yet everyone must evaluate this
very important variable for themselves by testing their
buoyancy with empty tanks.
The Harness And Backplate
Historically divers have bolted a backplate to the tanks with a buoyancy
compensator sandwiched between. This system provides a continuous loop of
2" webbing woven through a rigid backplate. Many people have replaced
the common metal (usually aluminum or stainless steel) backplate in favor
of a strong plastic plate. Still another evolution has been the development
of a soft backplate and harness. Some divers insist upon the need for a
redundant BC to provide lift. While many people merely use two of the standard
style compensators, manufacturers have responded to the demand for redundancy
with a dual bladder BC.
While the majority of experienced cave divers continue the use of the
standard backplate many new divers are opting for the newer soft pack.
Commonly divers buy the newest of the available equipment assuming that
any changes to a system must be improvements. The evolution of different
types of harness systems is really more complicated than simply being
an improvement over previous designs. Certainly one of the most hardened
realities is that manufacturers make money by expanding their product
line. New products yield more profit and slick new designs will often
encourage people to commit to another purchase. In addition, as technical
diving becomes profitable more companies vie for a share of the proceeds
further increasing the variety of available options. The educated buyer
should appreciate this variety as it allows one to choose the system that
best suits their needs. However, one must truly be educated in the many
subtle variations within the wide spectrum of equipment choices.
The evolution of the plastic backplate was probably a response to a number
of factors. However, the diver need only consider the net result of this
change. The plastic backplate is lighter and some see this as an advantage
while others see it as a failing. Many divers need weight to sink or to
compensate for the change in buoyancy caused by a consumption of air during
the dive. If one needs additional weight then a lighter backplate will
further increase the weight one must wear. In fact, many divers place
weight under the backplate or use heavier stainless steel backplates to
reduce or eliminate the need for a weight belt. Divers using a plastic
backplate also may break the plate, a situation that may be rather distressing
if one began to lose the tanks. While breaking a plastic backplate is
extremely difficult it is possible. The only real advantage plastic backplates
provide is the reduced wear on the divers webbing. Metal backplates can
over time wear away on diver's webbing. However this is a slow and gradual
process that merely results in the need for replacement when the damage
becomes prominent. The plastic backplates do in fact reduce this problem
but also force the diver to be creative in their use of weight buckles
to prevent the webbing from slipping and changing the fit of the harness.
Most of the communities seasoned pros prefer the stability and weight
of a metal backplate and prefer to replace the webbing every several years.
One must be wary of solutions to small problems that create significant
hazards.
The once common continuous length of webbing that dominated
the diving harness is now often replaced with quick
release buckles and two piece webbing. If one were to
ask a climber to use a plastic quick release clip to
secure them to a safety line the response would probably
be entertaining. Yet, that is essentially what many
new divers unwittingly request. Quick release straps
seem easy to remove because they are. They also may
release or break at the wrong time. Most seasoned divers
cringe at the thought of losing the tanks from their
back as should all newer divers. In many cases this
loss could prove fatal as the diver clings to tanks
whose negative tendency stands in stark contrast to
the divers positive tendency. It is possible to use
double end bolt snaps to secure these clips yet this
is unnecessary if one maintains the use of a one piece
webbing.
The evolution of the soft backplate was initiated with
the release of Diverite's Transpac. A phenomenal seller,
the unit fast became a popular system for new divers.
The Transpac and its peers are not necessarily an improvement
in existing technology but rather indicate a shift in
ideology. The early harness and backplate were designed
to securely hold the divers tanks close to the body.
Heavy cylinders must fit snugly or they will move on
the divers back effecting trim. The Transpac substitutes
a soft pack and reinforcement plates for the rigid backplate.
The most highly touted advantage to this system is the
comfort of the soft backpack. Interestingly enough these
new systems began to incorporate quick release buckles
and nonadjustable d-rings, items historically scorned
by the community. These systems often use fixed d-rings
occasionally allowing a couple of the 10-15 d-rings
to be adjusted. These systems can be fairly comfortable
and some people assert that they find their injured
backs are less strained by the system. However, these
systems are much bulkier, increasing one's drag and
profile, with more d-rings than anyone could really
use. The d-rings are smaller and in some instances somewhat
triangular reducing their usefulness. The sewn rings
are also more difficult to find by touch as they move
around much more than the fixed d-rings of the older
harness. Many divers seem to be very happy with these
systems, however those that go on to work with multiple
bottles often return to the more stable and lower profile
configuration of the standard harness system. Given
that most divers already wear a quarter inch or more
padding in the form of a suit the newer harnesses seem
to provide what few people need and sacrifice the stability
and cleanliness so prominently a part of the early cave
diving systems.
Weighted down by more than 100 pounds of equipment,
many divers believe that they must have very large buoyancy
compensators. In fact, many divers use BCs with as little
as 45 pounds of lift while others insist upon dual BCs
with a combined lift of 160lbs. Obviously, one's dry
land weight is inconsequential and a BC with 55lbs is
usually enough to float nearly any diver. Many divers
overweight themselves and then maintain a large reserve
of air in their BC. Air in the BC. merely increases
the drag resulting in a higher level of energy expenditure.
Some divers insist on a reserve BC while others feel
they are unnecessary. Generally the consensus is that
while diving wet in an area with a deep or nonexistent
floor (i.e. ocean or large cave) a redundant BC is a
good idea. Many people feel that a diver diving a dry
suit could use the suit for emergency buoyancy. This
assertion is quite reasonable but should be practiced
to determine one's proficiency.
In response to the technical divers concern over a
loss of buoyancy several manufacturers have incorporated
two bladders into one casing. These BCs have redundant
exhaust valves and inflator systems. One should be wary
of connecting both inflators at one time as a small
leak from the inflator could continue adding air to
the unaware divers BC. As the diver becomes more positive
they will usually try to empty their primary BC remaining
unaware of the secondary inflation. If the diver is
unable to correct this problem quickly enough they may
find themselves at the surface experiencing any number
of maladies. The redundant BC inflator should be tucked
away but within reach so that in the unlikely event
of a failure an inflator can be connected. The spare
inflator can be connected to the hose previously controlling
the failed BC or to a hose attached to the corrugated
hose but not connected to the power inflator.
Several of the new style BCs have become known as bondage
wings because the contain numerous bands of flexible
material that restrict the size of the wings and theoretically
decrease their drag. When the BC is inflated the bands
should stretch and allow the wings to fully inflate
and when the air is released the bands shrink down the
excess material of the BC. If one desires to use this
system they must attach the flexible bands when the
BC is inflated to insure that the bands do not prevent
full inflation. The BC. should then be checked in the
water to insure that the overpressure relief is not
prematurely activated. Opinion, of course varies on
the desirability of the system. As the wings get larger
measures are taken to reduce their drag. Many divers
still opt for the smaller size, eliminating the concern
altogether.
The astute diver can make some fairly simple changes
to their BC that will increase its ease of operation
while also extending its longevity. First, one may cover
the inner bladder with inner tube to protect its somewhat
fragile design. The Seatech and ProSub BCs have a tougher
casing then the early Diverite and are therefore less
prone to puncture, yet the protective tube can be used
for any style BC. The corrugated hose on nearly all
BCs is far too long and is often impossible to streamline
due to its length. By obtaining a much shorter corrugated
hose and coupling it with a custom inflator hose the
diver can significantly improve the cleanliness of their
system. Finally, one should check all fittings on the
BC and insure that they are secure. In some cases manufactures
use one wire tie to secure the corrugated hose while
a clamp would be far more secure.
Gauges are necessary pieces of equipment but people
often succumb to the "more is better" philosophy.
Two timing devices should be more than sufficient for
anybody's needs. The gauges should be wrist mounted
so as to avoid bulky consoles and the resulting dredging
effect they create. One's pressure gauge should be free
from a bulky console and mounted in a clean but accessible
area. A pressure gauge that is clipped to one's belt
keeps the chest free from clutter and limits the items
you will potentially drag in the mud. The advent of
hoseless gauges promises to solve all these problems
yet like most cure-alls I remain patiently optimistic
but as yet remain unwilling to bestow all my air management
faith in their reliability.
The body is the central component to any effective
diving locker and no discussion of equipment would be
complete without giving it a mention. Many debates have
revolved around the necessity of fitness in diving and
no doubt these debates will continue for years to come.
It seems that the most reasonable course would be to
evaluate the type of diving to be done and adjust your
level of fitness accordingly. The average diver should
be seeking good cardiovascular fitness with aerobic
activity- at least three days a week for a minimum of
20 minutes. However, good fitness can serve you in life
as well as diving and a thorough fitness routine will
leave you more prepared for the rigors diving can produce.
A person winded by a flight of stairs can certainly dive but their ability
to manage stressful, air critical situations is limited by their physical
response to elevated exertion. This may seem inconsequential in a leisurely
dive but in an emergency it can make all the difference. Certainly excessive
exercise could be a potential liability as scar tissue accumulation at
the joints could reduce circulation. However, too much exercise is indeed
a rare commodity.
Conclusion
The next decade of diving will undoubtedly be full of excitement and
prodigious change. Undoubtedly equipment advancements will continue and
many exciting advancements are bound to grace the diving world. Yet, regardless
of the level of change beyond the year 2000, two things will undoubtedly
remain constant. There will always be new equipment for people to obsess
over and there will always be people arguing over how that equipment should
be configured.
The preceding discussion attempted to shed light
upon some of the basic tenants within the Hogarthian
equipment configuration. As pertains to equipment
more is rarely better and the Hogarthian diver be
grudgingly makes additions to this minimalist attire.
One should not take from this discussion the impression
that safety equipment is dispensable and that the
Hogarthian diver intentionally accepts additional
risk. Quite the contrary the Hogarthian diver attempts
to remove all possible risk by designing a holistic
life support system that facilitates every dive. The
risk should after all be a function of the environment
and not the divers state of preparedness.
Jarrod Jablonski, Founder and President of Global Underwater Explorers
This article was first published on Gue.com
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