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Howdy Mr. Beard!
>I am getting mixed messages on equipment. Why all the need for
>redundant this and redundant that? Or is there a need? The required
>equipment list for a TDI Technical Diver course called for (amoung
>other items): a redundant bladder backmount BC, redundant mask w/bag,
>and a redundant bottom timer/depth gauge (read:computer).
Let's take each of these items in turn...
Redundant bladder BC... This is in case the bladder malfunctions and can
not provide lift. How does this happen: 1) puncture in bladder.
2>Inflator malfunction (or destruction) 3>Deflator malfunction (or
destruction). Now, how much air do you have in your BC to maintain
neutral buoyancy? If you have them inflated more than "just a little
bit", then you're overweighted. If you only have "just a little bit" in
the BC, then with NO air in the BC, you can still SWIM up.
And if you're in a dry suit, then you already have a redundant bladder...
Redundant mask... Ummmmm... why? Let's see, you can A) lose the mask or
B) break the mask. If you hit something hard enough to break the mask,
you've done some other things dreadfully wrong and your buddy is going to
end up holding your hand out of the situation you're in. (Think about
how hard you have to hit a mask to break it...). If your mask comes off
and you lose it, you can still see, and you're only going to turn your
dive right then anyhow. Sure, your Deco hang is going to be pretty
boring, but you can still get out of the water safely. I can read my
(important) gauges without my mask on, and all I _need_ to be able to
tell is how deep am I and what time is it for my Deco.
Redundant bottom timer and depth gauge... Here's where things get a
little iffy. I'm pretty sure that George will believe that this
redundancy is not necessary. Let's analyze this. Why do you need a
depth gauge and timer? 1) So that you know your maximum depth... Your
dive plan should already have figured that part out. 2) So that you know
how long you've been underwater... once again for the dive portion (as
opposed to the Deco portion) you should already know what the MAX time
will be, and if your timer (or depth gauge) fails before then, you're
coming up, right?
So the failure of Depth gauge or bottom timer during your dive is
survivable - you know what the maximum of both time and depth is.
HOWEVER, you need some sort of depth and timing device while doing your
deco hangs, and that's where it comes in handy. If you're doing it like
WKPP does, with safety divers, etc., then they can provide depth and time
measurements for your Deco. That is, I admit, the right way to do it.
Recognizing that not all of us have the resources to draw on like WKPP,
and that we're going to dive anyway, I suggest that you do have a second
timer and depth gauge. My backup is a Citizen Aqualand watch to back up
my computer's depth gauge and timer. Note that my backup is NOT a
computer (hell, I don't even use the computer as a computer, just a fancy
depth gauge and bottom timer).
>
>After veiwing WKPP's gear rigging video, I e-mailed George and asked
>about a redundant BC and mask. Their gear set-up was very clean and
>simple and ommitted these items. He replied that they are not needed.
>Is this because of a difference in disciplines (Cave v. Wreck)? One
>would think that the same gear configuration would suffice for both
>types of diving.
Yes, you can rig your gear the same for cave and wreck. I'm not a cave
diver (George is), I'm a wreck diver, and I saw nothing wrong in the
rigging in the video that precludes it from wrecking (unless you're going
porthole hunting in which case George left off the crowbar, acetylene
cutting torch, assorted wrenches dangling from his utility belt).
Hopefully, this has been of help.
-- Kevin --
-- Kevin --
kevink@ap*.co*
It is hard to disagree with a pro-survival decision,
It is even harder to engage in prolonged arguments
with someone who consistently makes anti-survival decisions.
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