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"S I L E N T I M M E R S I O N" <silent@cu*.ne*> (Subject: Re: A question
about who is the mouth) wrote about streamlining of scuba gear.
(Sidetrack: What is a scuba and what is not a scuba, exactly, by current
word usage? (I am English and was brought up to use the word "aqualung" for
open-circuit sets.) The word started as USA naval for "Self Contained
Underwater Breathing Apparatus" and at first seems to have meant frogmen's
oxygen rebreathers. A USA sport diving manual that I read in England in the
1960's talked about "air scuba" (= open-circuit with a regulator) and "oxygen
scuba" (= rebreather). But recently I have seen a tendency to use the word
"scuba" for open-circuit sets only.)
-------------------------------
I agree about streamlining.
Peter Readey told me that he tried a computerized mixture rebreather called
SMS2000 made by Carmellan Research; it was all in a big rectangular backpack
box, and he said that tail eddies etc behind its square back end cut half a
knot off his maximum swimming speed. (The "frog's back" angular-humped shape
of the modern Cis-Lunar looks like quite an improvement that way.)
I am certainly less agile in the water with a modern aqualung with up to 5
hoses radiating from the cylinder top (2 regs, to stab, to drysuit, to
pressure gauge) and a cylinder boot giving the cylinder a square back end,
and a stab with irregular surface contour causing yet more drag, than with my
first 1960's Submarine Products aqualung with one long thin cylinder with a
round back end without boot and no stab. And as for the effort involved in
rolling over! To me, "dressing in drag" is a good description of modern sport
diving gear, which is fine and safe in itself but its hydrodynamics in moving
through water fast is atrocious. I have dived with a naval frogman type oxygen
rebreather and with a 40-minute duration oxygen rebreather called a Salvus,
and the improvement in underwater agility is astonishing. How much work has
been done in hydrodynamic testing of a man in scuba gear like they do with
ships?
------------------------------
Sorry, but in diving what is DIR? (except an MS-DOS computer command)
------------------------------
Someone wrote about bad language on email:-
> Show me a list where he -is- banned so I can sign up right away.
Someone with experience in recovering diving casualties wrote that in his
opinion, if bad language on channel is needed to discourage bad practice and
so save lives in diving, then divers' lives matter more than whether or not a
few unprintable words get on the email. If so, then:-
> that practice is dangerous
is safety advice;
> that practice is fucking dangerous, and Mr.X who keeps doing it is a stroke
is understandable even if somewhat regrettable, but if it is needed to warn
someone off a dangerous practice, then it might pass.
But half a screenful calling Mr.X everything urogenital and proctological and
scatological that the author can think of, with next to no words relating to
diving or casualties anywhere in it, is for me too much and has drifted away
from the original purpose of the argument.
--
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