From: adb@herboid.uucp (Anthony DeBoer)
Subject: Re: Boyancy control with drysuits
Organization: Linda's Dragon Memorial Society
Date: Mon, 17 Aug 1992 23:49:58 GMT

Robin Roberts <rarobert@ursa9.cs.utah.edu> writes:
>In article <1992Aug17.031442.4636@syacus.acus.oz.au> johng@syacus.acus.oz.au (John GriffithsMel) writes:
>>
>>I've been using a dry suit for about ten years and I still use it
>>for buoyancy control. I use an ABLJ (horse collar) so maybe thats the difference
>>The peole I used to dive with in the UK also all only used their suits no the
>>BC. I was wondering why you use your BC??. Down here I only use the dry suit 
>>in the winter :-)
>
>Why use your BC?  If your drysuit floods (i've seen it happen), it won't be
>much help as a bouyancy control device!  Admittedly, you can ditch your 
>weight belt, but that still may not be enough bouyancy to keep you on 
>the surface with a flooded suit.  In addition, since most people wear
>dry suits in cold water, you have a real hypothermia problem - not the
>best position to be in!  A BC might be the difference between a blown
>dive day (and expensive dry suit repair), or a trip to the hospital (or
>worse).

So, why not use your drysuit for bouyancy control?  Certainly, I wear a
BC for backup flotation, and can use it in the event of a suit puncture,
and I test it before every dive, but that doesn't mean I have to use the
BC for bouyancy control during a normal dive.  In fact, I'd probably
be better off with an ABLJ instead of an North American-style BC because
of its emergency flotation properties; it will float you face-up, while a
BC can float an unconscious diver face-down (unfortunately, they're hard
to come by this side of "the pond").

Note that most drysuit manufacturers, and to the best of my knowledge the
certification agencies as well, recommend wearing a BC/ABLJ and not
relying on a drysuit alone for bouyancy.

As a further safety precaution, since I don't use the BC during a normal dive
anyway, I run it from my pony bottle so that a primary air supply failure
doesn't leave me without bouyancy.

>Like i've said before - air in the dry suit is only for keeping warm and
>preventing squeeze.  Using the suit in lieu of a BC is asking for trouble,
>like having too much air in the suit... moving the wrong way...  and ending
>up in an uncontrolled ascent in the feet-up position. 
>(Can you say, "polaris missile"??)

If you need that much air in your suit, then yes, you might be better off
working that way.  I don't need too much air in the suit (and also, it
being a Viking, I'm not dealing with suit-material squeeze), and the flip
side of the coin would be having to manage air in both the suit and the BC
on ascent.  If that becomes "operator overload", you're dealing with an
uncontrolled ascent too.  But then I have a lot of dives in my suit and
can count on not getting into a "feet-first".  IMHO that's an extremely
important thing for any drysuit wearer to master BEFORE going deep in the
suit.
-- 
Anthony DeBoer   NAUI # Z8800, D5482 | Why watch TV, when Netnews provides
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