Steel tanks - what's what...

[marcbeaudry]

i've got an opportunity (to shoot myself in the foot ??) to purchase a used
steel tank with a hydro good for another 3 years.
it's an older US Divers - 104
thing is...i'm not sure what I normally dive with ? i know i know - completely oblivious.
it's with my head hung in shame and ignorance that i ask such a stupid question.
i dive steel tanks only - what size tanks would your average dive shop typically use for classes and rental stock ? those 80 ad 90's ?
i'm not sure how big a transgression i'm making by moving to a 104 - if any at all.
fwiw - i'm likely to swap out the existing valve for a din type to suit my reg.
thanks in advance for some insight...
marc

 

[Scared Silly]

Most people learn on an Al80. But given you learned on steel I am not really sure - If a HP cylinder I would guess a HP100. If low pressure perhaps a LP85. Why don't you call the shop you normally get your cylinders from???

 

[msg]

You will need to check with your LDS to see what they use. They could have been using 72's. The only thing that will be different is the amount of weight that you will need to be neutral. Does the tank in question look about the same size as what you have been using? This may give you some insight.

 

[IceBergSlim]

Make sure the yoke valve is not the type that is convertable to DIN with an allan wrech. It would suck to go to the expense of changing your valve if you did not have to.

 

[DA Aquamaster]

I am not sure what an older US Divers 104 would be. Is it steel or aluminum?

 

[rstofer]

Get the headstamp info like 3AA (steel) or 3AL (aluminum) or whatever. An old LP 72 reads 3AA2250 and it's really a 65 cf tank that only gets to 72 cf if it is '+' rated and filled to 2475 psi. Or, at least, that's the way I understand it.

You should always log your tank info with your dives. You can look back and see your average depth (if available) and air consumption. It is also useful to correlate your ballast with your tank as, in may cases, the tank contributes to ballast. At least when you compare an Al at +4# at the end of the dive versus an HP 100 at -2.5#. You can carry 6# less ballast and the HP 100 is lighter (except it is carrying 2# more air).

Richard

 

[marcbeaudry]

i will definately track tanks in my dive log...seeing as how there are only 8 entries in it so far....it shouldnt be hard to rectify the problem -
ok - here's whats stamped in the tank under a healthy layer of yellow paint :
US Divers Co. 17
1CC3AA2250

K87364
USD
11 06 84 ( date i assume)

and in an area that has not been painted -
6 GAM 87
(iron cross stamp) 1026206

the tank is roughly 8'' in diam - by roughly 26'' (ish) inches tall -
and sadly....has a Sherwood 5000 YOKE valve - i do have a din to yoke adaptor mind you...

thanks for any help identyfing this - the previous owner said it was a 104 - but he wasnt sure why he thought thats what it was...he hasnt dived it since 02' had it hyrdoe'd in 06' - and it hasnt been used since -still on it's last fill in fact.

cheers.
marc

 

[halocline]

Are you sure it's not 7" in diameter, actually 6.9", and a little over 25" without the valve or the boot? If those are the dimensions, you have a LP 72, which is a really nice tank for doubles and/or vintage diving, or any dive where you don't need a lot of extra air. ICC is the certifying agency for the cylinder, 3AA2250 is the material and service pressure (2250 PSI) 6/87 is a hydro date; is the "iron cross" a "+" after the date?
The 1026206 might be another hydro, but it would be separated so that it was either 10 06 or 1 06 (October or Jan) with other numbers and letters in between, which are the hydro facility ID.

I don't know that much about vintage tanks, maybe there was a 8" 2250 PSI scuba tank that's 104 cf. I'm sure someone will know.

You'll need a VIP, but if it's been stored with good quality (meaning dry) scuba air since the last hydro, that's a good sign. If you can tell if the tank is galvanized, that's important, I would not buy one that's not galvanized, and you probably want to avoid a tank that has the vinyl lining inside. Any chance you can verify those things with the seller before buying it?

If it's a 72, galvanized, clean inside with 2 years of hydro left, I'd pay $50 at least for it. I think a fairly typical price for them out of hydro is $30-40, and the hydro is probably worth $20. Those are my opinions but there are others with a lot more experience who might differ.

An easy way to measure the diameter is to measure the circumference. If it's around 21.5", it's a 6.9" tank.

 

[Jimmer]

I don't know that much about vintage tanks, maybe there was a 8" 2250 PSI scuba tank that's 104 cf. I'm sure someone will know.

Well I own a 104 from 1972, with the DOT stampings as opposed to ICC. It is 8" but it is 2400psi and not 2250. I would suspect this is a good old steel 72.

 

[marcbeaudry]

yup - closer to 6.9'' and over just over 25inches tall - so an LP72 sounds likely then -
the iron cross is placed before 10216206
so it appears as though i'm setup for Vintage Dive Club....
now...lp72 - implies LP- low pressure ? and the 72 = 72 cubic feet of compressed gas ?

my first dives have been primarily with what physically appear to be 80's - although i'm one big muther and need the additional weight so they kept tossing the odd bigger steel tanks at me - i suspect 90's ?
marc