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Date: Tue, 24 Aug 1999 02:26:44 +0200 From: Hans Petter Roverud <proverud@on*.no*> Subject: Bondage wings --------------- It seems safe to say that opinions vary from "This is what we see dead divers wearing" to "These wings are the design used by most Northeastern wreck divers and we have no problems whatsoever". For those who think I'm beating a dead horse -- I am, but I'm trying to add the plausible reason why "bondage" is no good idea. I know a lot divers using "bondage" without any incidences. I also know one who jumped in and found himself on the bottom at 100' in no time with a wing that didn't hold air. What happened? A low pull dump had gotten wedged behind his backplate and was stuck. Since the bungee cords work as an auto-deflate, any minor leak will let the air out of the wing in no time. With a non-bondage wing a low dump valve stuck open wouldn't actively purge the wing -- it would just bleed air out as the wing approached full volume. You'd still get ample buoyancy in a horizontal, slightly head-up position. The same would go for any otherwise insignificant puncture or faulty fitting. Thus, I believe the combination of bungee auto-deflate and jammed pull dumps to be _the_ deadly combination. I don't choose either feature. If you do, please get rid of the balls on the pull cords or the bungee. These features in combination may give you a catastrophic failure. Why not get rid of both? Would for instance an OMS be unwieldy without the bungee? At any rate, next time bondage wings won't inflate and hold air, check if the pull dumps are stuck in the open position. BTW, what purpose does low pull dumps really serve? Without that bungee assisted auto-deflate one would never be able to purge air by pulling a low dump anyway -- since air likes to float in water you'd have to swim head-down to bring the air to the low dumps. (OK, so maybe you do assume an inverted position sometimes but do we really need alternative dumps for any conceivable posture?) Rather, dump air through the corrugated hose and lose those pull dumps, the bungee or preferably both! The fact that it's all hunky dory as long as the balls of the pull dumps don't snag or get wedged doesn't mean it's a safe combination. You've got an auto-deflate wing and _any_ minor leak will purge it. The bungee puts a constant strain on the wing and will collapse it whenever the opportunity presents itself. If you elect to keep bungee as well as pull dumps, at least check that the wing holds air before you jump in. If a pull dump is jammed open you'll know the moment you try to fill the wing. regards, Hans -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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