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Jim,
You write:
>Using the DS as primary is done by lots of divers. I don't think its a
>bright idea, certainly not comfortable, but to each his/her own. Using
>your wings as primary is the ideal, if you have to use your DS, you deal
>with it.
The reason I asked "why not" is because I thought the answer would
probably be that Dry Suit buoyancy control was in some way less efficient,
comfortable, safe, or practical for many divers but I wanted you to say it
since I have never dove a dry suit and can not speak from first hand
experience.
-----------------------------------------------------------
>In many critical backup systems there is a "get home" strategy and this
>includes parachutes, brakes, engines (like a twin engined airplane),
>pumps, to name a few off the top of my head.
>The idea being that the primary system is extremely unlikely to fail, but
>just in case a secondary "get home" system is available.
And, where getting back alive and well is a high priority, the limits of
safe penetration (up, down, or sideways) are dictated by the capabilities of
the diver using the "get home" system during a bad storm rather than by his
capabilities with the primary system on a nice day. I'm sure this is
violated as a matter of course with many divers at all levels such as when
they buy a cheap octopus.
I think it is unwise for a diver to think in terms of "getting home" as a
pilot in a crippled plane does when he gives up trying to fly and jumps out.
The diver must continue to fly somehow no matter what. We must "dive" our way
out of trouble without the luxury of shifting to an escape mode that frees us
of the burden of having to continue to perform under pressure.
It seems to me that choosing to use a dry suit for back up buoyancy is to
limit yourself to what you can safely return from using dry suit buoyancy
control. So, for the diver to whom the bladder is the superior method of
buoyancy control, a second bladder would extend your safe range to what you
can do with a set of wings. I am assuming, of course, that there will be
some deterioration of your performance and endurance or in your status if you
have to resort to a system you don't like or prefer for some reason.
I can't really see a problem with a second hose safely tucked away but
accessible, though I would do away with the LP hose as I have noted. This
would not violate hogarthian thinking if it were needed to make the intended
penetration safer though it might cause problems with some specific
configurations that also adhere to hogarthian ways.
The WKPP rig is an excellent interpretation and application of hogarthian
philosophy but so is a well designed submarine if the dive requires that you
go to 3000 feet. The hogarthian philosophy is a stand alone tool
universally applicable to a wide range of situations from the new diver to the
sub pilot. It is not the WKPP or any other specific configuration as some
might come to think from the tone of the tech lists.
You know, if you guys could get over your fear of the dark you could dump
those big AUL light canisters you haul around and another inflator hose won't
be such a big problem.
------------------------------------------------------
> Now if the bladders in wings were popping like zits on an adolescent's
> face, well maybe you have something with dual bladder wings.
Yes, you would have dual junk ! "Dual bladders" is only a worthwhile
back up strategy if failures are rare and not caused by factors normally
common to both sides.
You've got to be able to trust a back up system to get you back out all the
way in less than ideal conditions and task loaded. Starting out with a
bladder with a known propensity to pop (even if the second is less likely to
fail) means that your poorly chosen two is not even one (two is one and one is
none).
Whatever back up systems we use in diving should be as good or better than
the primary in every respect because this is what actually determines our
limitations - not the primary system. This system is made up of a combination
of the diver and the equipment he will be using so that everything about the
divers head and body effects the performance of the system as much as does the
equipment suitability.
No doubt the reduced clutter of using the dry suit as back up is preferable
but only to the limits from which you can return with it safely.
> But even then I would argue that it makes more sense to design a reliable
> primary rather than having identical redundant systems to make up for
> some design deficiency wether real, or as in this case, imagined.
What I am suggesting is two systems you have equal faith in and capabilities
with rather than one you like and one that is a compromise for some reason.
Otherwise limit your range to what you can handle easily on the compromise
under stress.
Chuck Boone
--
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