Newsgroups: rec.scuba
Date: Thu, 12 Nov 1992 11:41:18 -0500 
From: "Peter A. Simon" <ps3p+@andrew.cmu.edu>
Subject: re: how much weight do I need 

I mispoke badly.  My apologies.  I *always* use a BC with a wet suit but
I, too was brought up with "horse collar BCs."  Originally they were
called "life vests" (because that's what they were used for
originally--life vests for military aviators and also they were the
things you found under your seat on an airplane before the advent of
floating cushions).  This practice ended when New England Divers was
succesfully sued by the family of a diver who drowned.  The claim was
that calling them "life vests" was fatally false advertising (no
kidding, you can look the case up--this was in the late sixties).  So
they became "buoyancy compensators" (and for a long time weren't sold by
mail due to the liability).  When I could afford it, I bought a Fenzy
which was basically a heavy duty horse collar with a 5cf (@3000psi) pony
bottle attached (replacing the useless at greater than 30fsw CO2
cartridge of the life vest).  Both could be inflated by mouth and I did
this even with the Fenzy, preferring to save the pony for emergencies
(it could also be used as Spare Air).  It might sound bizarre to those
used to auto-inflators to take the regulator out of your mouth to puff
into your BC but this was absolutely no big deal.  A big advantage of
the Fenzy was that it had an auto-dump to prevent overinflation on
ascent (you had to remember to do this manually with the life vests).

I don't know the buoyancy differential of twin 95's (to figure it out
I'd need to know the filling pressure, have reference to a periodic
table for the atomic weight of O and N, and know if 95cf is nominal or
actual) but again, in the bad old days, I avoided certaqin US Divers
aluminum tanks like the plague due to the fact that they were four to
six pounds light when empty (vs ~ 2# for a steel 72) and when you're
manually inflating a BC you want to minimize that kind of change over a
dive.So I, too, find some form of BC irreplacable for trim and surface
swimming.  My problem is using my *breathing* air supply for buoyancy,
and the cost and complexity of the systems used today.


>  
> A BC has two (2) bennefits when worn with a dry suit.
>  
> 1)  The air in your BC can't race into your boots and trigger an uncontroled
>     feet first ascent.
>  
> 2)  If your dry suit was ever punctured (a bad thing), then you still have
>     some buoyanct control.  (I had a reverse case two dives ago.  My BC 
>     inflator hose (from mouth piece to BC) cracked open.  My suit was my
>     backup.  Redundancy.  {The word almost sings...})
>  
> 3)  The limited shifting of air in a BC makes trim control a lot easyier.
>  
> None of these seem to me faddish of foisted reasons by equipment
manufacturers
>  
> and sellers.  But hey, what do I know...
>  

How about a return to the Fenzy (with some thought to making it a bit
more comfortable than the original), a BC with it's own, self-contained,
integrated inflation system via an unobtrusive pony bottle?  Saves the
problem of splitting inflator hoses (!!! That alone highlights my
objections).  It would be simpler, less cumbersome, and, hopefully,
cheaper.

> Just another man's (different) experiences, not necessarily better or worse
> than any other's.
>  
> craig

Peter Simon
NAUI Inst. #1434
Newsgroups: rec.scuba