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  JOHNCREA <JOHNCREA@de*.co*> wrote on Fri 25 Nov 1994 17:27:22 -0500 (EST)
(Subject: Re: Inverted tanks.):-

  > I really think that hydrodynamically it probably doesn't make much
difference between normal tank config (with all the regs, plus the tank cross
sectional area contributing to drag) vs an inverted tank config, where the
cross sectional area is probably the major contributor to the tanks drag.
  Again, as has been said before, the aqualung has the hydrodynamics of a
brick, particularly in these days when safety rules insist on the diver
wearing several extra drag-causing bits and pieces. Where speed and agility in
the water matter, a small rebreather, preferably in a streamlined (e.g.
blister-shaped) backpack, will win hands down any day.

 > ... (plus, most tech divers are going to various types of neck straps on
the primary second stage specifically to avoid the problem of the dropped
second stage.)
  (1) All or most ordinary aqualung single-hose regs that I have seen, have a
neck strap on the second stage. I thought it was the general practise, not
only for tech diving.
  (2) A few years ago I bought new a 1960's-style twin-hose regulator made in
Spain by Nemrod, and its mouthpiece had a neck strap to stop the diver losing
it behind his neck. This should be borne in mind by people with rebreathers
with that sort of breathing tube loop round the neck. And (like the BSAC
(British Sub-Aqua Club) used to) they should practise the backward roll
underwater, as that was often the easiest way to recover a twin-hose
mouthpiece which had floated up behind the diver's neck.

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