Stuart

>I thought the key to Hogarthian diving was survivability.

Hmmm.  Survivability is what all diving is about.  Hogarthian rigging and
DIR is one of the best ways to achieve it.  Staying out of the water is the
other.  But then I've seen the light.

>Is there anyone out there who is one hundred percent sure that in an
>emergency they can honestly say they would reach the valves EVERY SINGLE
>TIME? All it takes is one time to fail and, basically you die.

Can you guarantee EVERY SINGLE TIME that you remember to decant on schedule.
Secondly, using your argument, what happens if you fail to un-isolate
because you can't reach your valves EVERY SINGLE TIME.  You now have half
your gas and no equipment failure has occurred to cause this.

In any case, the argument is irrelevant, I can think of examples in both
scenarios where I could fail to reach my valve or to decant.  The trick is
to identify the most likely risk of the two and deal with that.  IMHO, most
accidents can be attributed to human error, not equipment failure.  This
being the case, don't have a setup that relies on the human doing something
when that "something" can be avoided in another scenario.  You have adopted
a strategy which relies upon the human not failing during the course of each
and every dive.  With a Hogarthian rig, in the context of isolating, there
is still a chance that the human can fail but that failure has to occur
*following* an equipment failure.

If you cannot isolate don't get in the water.  But you say you can do this
reliably.  Don't let paranoia clouding your judgement.

> I hear loads
>of rhetoric but not a lot of justification to your arguments. Have I just
>dared challenge the High Lords of the WKPP or is there a more practical
>reason why this method is flawed?

No, you are suggesting a dangerous procedure.  See above.


>I'm assuming most of the hostility is coming from the US. I don't dive open
>water except for training purposes, so I'm speaking from the standpoint of
cave diving.

Well here's some from a UK diver who happens to be in SA at the moment.

> European cave diving is a million miles from the springs of
>Florida, so I have a slightly different view. After three or four hours in
>flowing, zero vis cave water, barely above freezing, I cannot say for sure
>that I could shut down my valves safely. At least I'm being honest with
>myself, not shrouding myself in bravado. I apologise for being imperfect
>but I'd challenge a veteran Yucatan or N. Florida cave diver to get more
>than 100ft into a UK sump.

OK, so your point is that when you are cold, isolating is more difficult.
True.  I've Dived Dorothea in March and doing anything with your hands is
difficult.  This is where you have to ensure your equipment can be reached
and operated even with cold hands.  If it becomes difficult get warmer
gloves, if there is still a problem, make sure your isolator will spin by
friction and not need a firm grip.  Maybe you have to service it more often,
but with the right equipment isolation is not an issue.  If you try all
these things and can't isolate reliable, then restrict the duration of your
dive.  Adopting your SOP is increasing your risk for all dives, not just
those where you have cold hands.

You have to un-isolate with your procedure, so the above applies.  But what
happens if you are so cold that you cannot isolate - now you only have half
the gas available and no equipment failure has occurred.

>That, I think, is the key. We are flawed beings, we do not always succeed,
>so why fool ourselves into thinking that we are invincible. Accept that
>sometimes things go wrong, sometimes we get more tired than we realise,
>sometimes we get more stressed than we expected.

So if we are so flawed, why do you adopt an approach i.e. decanting, that
relies upon this flawed individual.

>I can reach my valves just about every time I try it, but I cannot convince
>myself that I will do it when I need to. The method I use is developed from
>that used by the British Royal Navy, who have one of the best safety
>records amongst the military.

They do this as they operate in situations of zero visibility and cannot
read a gauge, so have to rely upon draining down one of the cylinders,
decanting, draining down, decanting and then ascending.  BTW, they probably
have one of the best records as they are British :-)

> The vast majority of European cave divers
>still favour independant
>tanks and we haven't had a fraction of the deaths which have occurred in
>the US and Mexico. The British CDG is the oldest cave diving organisation
>in the world, they have been using independant tanks since they started
>using OC (the CDG were using rebreathers before the first scuba sets were
>even imported into the USA) and they have produced the best, safest and
>most prolific cave divers in its history. I think it is telling that until
>the WKPP started using Halcyons that the longest cave dives in the world
>were done in Europe by European divers using independant rigs. I haven't
>noticed too many US or orthodox DIR divers having much success over here.
>Again, maybe I've missed something.

I have no experience of cave diving in UK conditions and shall refrain from
answering even from a theoretical point of view.  However, you don't provide
any statistics to back up your point.  Anecdotally, I understand that there
are a small number of active divers in the CDG many less than the WKPP, so
comparisons are not so easy.  Besides, they probably have one of the best
records as they are British :-).

<snip>

>Heresy, blasphemy, I've got my long hose (which I breathe) on the left
>post. If the valves contact the roof going through a restriction then which
>knob could get turned off accidentally? The left one, which I'm breathing,
>which I notice, which I turn back on. Suppose I'm breathing off the right,
>my partner needs gas, grabs my reg, I switch over and get no gas. Or worse,
>he grabs the short hose and he gets no air.

So where is your wing inflate?  If its on the left, you've lost your ability
to control buoyancy and your lose your breathing regulator at the same time
(if you roll off your left post).  Not a good scenario.  If it on the right,
buoyancy is OK, just have to switch regulators and/or turn on left post.

If you breath of the right post and buddy needs gas he gets it.  You switch
to backup and find it has rolled off, you are out of gas.  Now I ask you,
who is in the best position to sort out an out of gas situation with your
equipment: you or your stressed buddy.  Besides, you can breath from your
wing inflate, if you have this on the correct post, whilst you sort the
problem.

One other point about breathing the left post with long hose is that, yes
you notice quickly when it rolls off and can do something about soon after
it happens.  However, you *have* to do something about it immediately.
Whereas, if you breath the right post, you have all the time in the world to
spot that your SPG has not changed.  Besides, to roll off the left post
*and* have your buddy run out of gas is two failures which is very rare, but
still manageable.

>BTW. I have a very comfortable, crushed neoprene drysuit which gives me
>shit loads of flexibility and I can reach my manifold every time. But all
>it takes is once not to.

Good for you, so why are you creating a problem for yourself?

>What kind of imbecile would put the contents gauge on a different regulator
>from the one being breathed in a manifolded rig.

All Hogarthian divers.

> Once more, mistakes get
>made. For example, a manifolded diver jumps in the water, swims into a cave
>then realises the needle on his gauge hasn't moved in the last fifteen
>minutes because he forgot to check that the isolator was open. He could go
>on forever, calmly thinking he had the lowest RMV on the planet. It's shear
>stupidity, but it happens. If the gauge is on the reg he is breathing from
>then all that will happen is that he will hit thirds in half the time he
>would expect.

Cases for both points of view work here.  The issue is that a failure has
occurred with a Hogarthian diver for the diver to have to isolate, rare but
not impossible.  In your case, it is your SOP.  Crazy!

>I'm not knocking the originators of the Hogarthian rig, I'm knocking the
>disciples and WKPP wannabees who blindly do without thinking and cannot
>tolerate being questioned. Everyone who can achieve perfect performance
>every time gets my respect, I am simply a humble, flawed diver with a
>deep-seated fear of not being able to breathe. In later years I'll pray for
>forgiveness for my heresy of daring to question Saint George but for now my
>blasphemic gear and I shall retire to our cave.

Isn't it odd how people see the same facts and come up with different
conclusions.  I suppose that's why Darwinism was discovered.

David Shimell
Project Manager, Sequent Computer Systems Ltd., Sandton, South Africa.
Email: shimell@se*.co* <mailto:shimell@se*.co*> 

--
Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'.
Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]