sorgatz@ttidcc.UUCP ( Avatar) (08/09/85)
< 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.)lamia@lsmvax.DEC (Walt Lamia - 231-6193 - MRO2-2/8D2) (08/11/85)
I'm an new diver (just certified last week), but while at the dive shop the owner was telling me about a new STAINLESS STEEL tank he saw at a show. It's supposed to be shorter and narrower than a standard tank, but still hold 80 cu. ft. at 6000 PSI! Plus it should NEVER corrode. Trouble is, he thinks it'll retail for over $300. He thought that if the prices ever come down, this will become the standard tank for scuba diving. %Walt
sorgatz@ttidcc.UUCP ( Avatar) (08/12/85)
Keywords:Stainless Steel Scuba Cylinders
< munch! gobble! chomp! chew! Why don't "THEY" fix this bug? >
I have seen those tanks that Walt referred to. Yes they are a smaller size
than a regular steel 74.2, and yes they do hold 80 cu ft @ 6000psi _BUT_
most places that vend air can pump (MAYBE..) to 4500. Most boats have only
2000psi available. This is the reason I purchased a Scubapro steel 96. The
rated cubic displacement is @ 2640psi (that's counting 2400psi working + 10%
overfill which is allowed for the 1st five-years!) With a 2000psi fill the
tank is about 83 cu ft, or so I've been told...maybe I should check this with
some of that fancy math stuff! (-| The buoyancy factor is -6lbs full/-3lbs
empty by my testing. It seems to be a nice tank. It only cost $275, and while
the that's close to the cost of a Justin Stainless (of Chanute, Kan) Tank
the practical use of a scuba must take into account the available pumping
pressures. One other point-98% of the regulator 1st stages are only rated to
3000psi. If you try to use your regulator with >3000psi, the yoke will let-go!
If the industry goes to 6000psi, I think I'm gonna setup an NC 5-axis to
manufacture 6000psi rated replacement yokes/1st stage cases!!!
-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 known what was destroying them!" -Dr. Morbius F.P.)atkins@opus.UUCP (Brian Atkins) (08/14/85)
Does anyone out there have any first hand experience with dual
tanks? Some say dual 50s are nicer to ware than a single 80, can anyone
remark on this?
Also, I have seen dual tanks with a manifold valve system, and
with just a cross connection. What does the manifold do and how important
is it?
Thanks
Brian Atkins ...{attunix, hao, allegra, ucbvax}!nbires!atkins
NBI Inc., P.O. Box 9001, Boulder CO 80301 (303) 444-5710