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On Sat, 23 Oct 1999, Dave Sutton wrote:

> >Dave -
> >
> >What do you use for buoyancy control when your drysuit springs a
> >significant leak?
> 
> First, the only failure of a drysuit that will cause an immediate and
> catastrophic loss of all ability to hold air is a zipper failure. In 25+
> years of using drysuits I've not seen a total zipper separation

I have, and in only 5 years of diving. And another case where a DUI TLS
sprang enough of a leak in a boot to totally flood the suit in a few
minutes.

I don't doubt the reliability of drysuits in general. But it takes only
one failure of this nature to convince me that betting my life on a
drysuit is stupid.

> I've never seen a drysuit flood to the point where it cannot be used for
> some bouyancy control.

A zipper separation, or failure to close the zipper completely, would
certainly render the suit useless for buoyancy control rather quickly.

> And, please remember, I use a Viking suit for the exact reason that it
> -does not- change bouyancy with depth, thus I can weight myself
> essentially neutral on the surface and any added air is merely for
> warmth.

You probably loose 6 or more pounds of ballast during a dive due to gas
used. That means you've got 6 more liters of gas in the suit at the start
of each dive than at the end. How do you manage that bubble?

> but I'm not overweighted, and in fact can swim to the surface
> with a completely flooded suit in all of my gear (and have gone to
> the quarry and proven it by having a buddy unzip my suit for trials).

You must be pretty heavy, and that swim would take a tremendous amount of
effort! Not a good thing to do at the end of a long dive with a
significant deco obligation IMO.

> Now, for -last-ditch- stuff. You can always drop weight. For me that means
> ditching my hammer and crowbar first and then maybe lead in a dire
> emergency. Lastly, there is always that handy 50 pound liftbag attached to
> my reel for setting up off-anchor deco. Either grip it and go (not best) or
> simply set up an upline on the bag and climb the line. Since we are talking
> -maybe- 6-8  (so maybe 10-15) pounds negative even under a zipper
> failure state, this is easy. Post deco cut the bag free, drop weights and
> swim the bat to the boat.

Seems workable. But don't you think you're putting yourself at risk having
to work that hard during the deco phase of a dive?

> Remember, in many thousands of witnessed drysuit dives I have never
> seen anything this catastrophic occur.

Here's where we differ. I have seen a failure of this nature, and I call
that significant evidence of the possibility.

> Bottom line, I personally do not use a BC at all, unless diving -very- heavy
> bottle rigs in which case I use a Dive Right wing on my backplate to carry
> the bottles to neutral. In this case, of course, there is a BC too.

Why don't you use the BC all the time? What advantage is there in *not*
having it?

-- 
Art Greenberg
artg@ec*.ne*







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