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Date: Sun, 31 May 1998 18:11:59 +0200 (MET DST)
To: techdiver@aquanaut.com
From: Hans Petter Roverud <proverud@on*.no*>
Subject: Cold water weight requirements
There's been a lot of discussions on weights -- most of them focusing on
V-weights rather than weight belts. Anyway, this is not about where you put
the weight -- I'm just puzzled to see the small amount of weights people
claim they need. To me this sounds a bit like the BC volumes that don't
match their tested lift capacity...

We're talking a membrane drysuit, a thick underwear (since insulation is the
whole point), doubles and stages. To me this means 30 - 35 # of weights and
I see people listing 10 - 20 #! 

Heavy tanks and stages may be a mixed blessing in this respect since there's
no way to avoid the loss of buoyancy as you drain your tanks. Since it makes
sense to be able to retain a comfortable inflation at deco stops with
near-empty tanks we're talking a weight loss from gas consumption in the
range of 6 - 15 #. Put differently, if you go into the water neutral you'll
end up being too buoyant at the end. Wings are needed primarily to bridge
the gap between "start weight" and "end weight" due to gas consumption. That
is, some wing inflation at the beginning and no wing inflation during
decompression. Conversely, if you still need air in your wings at the end of
a dive, you're overweighted.   

I may incorporate a V-weight when I get a backplate (until now I've carried
up to double 100s with the two cam bands of a Zeagle) but I see no way to
store 30 # as V or P weigths. A combination of V-weight and lighter belt
would work. I've got a thick Thinsulate with clothes beneath it and love all
the air/argon I can pump into it, particularly in the winter (4 C/40 F
water). The near-pinch inflation doesn't attract me since the entire point
is to stay warm. 

Slightly besides the point; I feel the air displacement issue is exaggerated
-- if you're used to diving a drysuit you won't need a near-pinch inflation
to stay in control. I've been diving drysuits for almost 20 years and really
miss the air displacement if I dive a wet suit! I find myself raising arms
or legs to get some air into those parts and wonder for a split-second why
they don't stay there despite the effort. Thus, I reflexly take advantage of
some air displacement and miss it when it's not there. Ankle weights on a
drysuit, for instance, would utterly limit my ability to "fly" the suit
since it would be hard to hover effortlessly. (Tried it twice -- felt like
ball-and-chain). Quite another issue is over-inflation of the suit -- that
is, putting more gas into it than you really want, to compensate for being
too heavy. Any flames on this issue will be warmly appreciated; however, do
not blame me for putting more gas into the suit than I really want!

Anybody in the northeastern US/B.C/Alaska or Britain care to share how much
weights are needed for a comfortable inflation with near-empty tanks? 

regards,

Hans Petter Roverud
Norway



 

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