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Path: utzoo!linus!philabs!ttidca!ttidcc!sorgatz
From: sorgatz@ttidcc.UUCP ( Avatar)
Newsgroups: net.rec.scuba
Subject: steel vs. aluminum tanks
Message-ID: <656@ttidcc.UUCP>
Date: Thu, 8-Aug-85 22:17:50 EDT
Article-I.D.: ttidcc.656
Posted: Thu Aug  8 22:17:50 1985
Date-Received: Sun, 11-Aug-85 07:02:52 EDT
Organization: TTI, Santa Monica, CA.
Lines: 41

< munch! gobble! chomp! chew! Why don't "THEY" fix this bug? >
 Here I sit, typing away at what might be the last message to ever get posted
to net.rec.scuba...shudder! Would "THEY" really remove such a nice newsgroup?
 Annnyywaay..I recently did a 'side-by-side' comparison of the buoyancy factor
of each type of tank, in a pool. The tanks were:

 a) aluminum LUXFER, 80 cu ft.
 b) steel PRESTEEL, 74.2 cu ft.

 The two tanks have approximatly the same weight when full, in submersion the
steel tank provides -4lbs of buoyancy whereas the aluminum one is just a bit
over -3. The real surprise, however, is that when the tanks are 1/2 full the
aluminum 80 is +1lb. The steel tank was NEUTRAL when empty, and at the 1/2
point still has a +2. The aluminum 80 when empty was exerting better than +2!

FACTORS:    1)   I used a cheap fishing-scale and the same monofiliment sling.
	       (the accuracy of which is +or- 8%) this may make these figures
	       a bit low, if the out-of-water tests were any indicator.
	    2)   Things in the pool, of course, have less buoyancy than they
	       would in salt water. This could be corrected.

OBSERVATIONS: When I use the aluminum 80, I need 28lbs of weightbelt ballast.
	      With the steel 74.2 this is only 20-24lbs!
	      The bottom time(for me at least) is not greatly different.

CONCLUSION: I'm gonna buy a steel 96 and see if the buoyancy/bottom times are
	    more in my favor. (-:
(it sure would be nice if someone would come out with a TITANIUM cylinder, I
think about 6000 psi in a profile like a steel '60 would be great!)

-Avatar->
Erik K. Sorgatz
Transaction Technology Inc. (Citicorp's R/AD West)         ... . ... . ...
3100 ocean Park Blvd. (zone V1)                            . | |..|..| | .
Santa Monica, Ca. 90405                                    |.|....|....|.|
USENET path: {garfield,lasspvax,linus,cmcl2,seismo}        |.|....|....|.|
	     !philabs!ttidca!sorgatz                       | | ...|... | |
("..My poor Krel! Even they must have evolved up from the  ..| | .|. | |..
  mindless primative..after a million years of shining sanity, they could
  hardly have know what was destroying them!" -Dr. Morbius F.P.)