Tank size for a short guy:

[KD8NPB]

I am 5'8, 150 lbs. My SAC varies at about 0.50 to 0.65.

Currently, I am using double LP72s. However, after a boat dive, I have discovered that they're a bit much of a pain in the butt to deal with. They also provide a bit of an excess of gas for my needs.

I would like to switch to a big steel single, however, I'm not sure of which yet...something for NDC / Nitrox diving. Ideally as well, something that I can double up with a manifold + bands in the future for some heavier saturation diving than my LP72s will be able to provide.

LP95s maybe? HP100?

I do like low pressure tanks, they're easiest to get a proper full "fill" with. However, I won't object to 3000 psi rated tanks either...nothing higher than that please.

 

[Captain Bil]

I am almost exactly your size at 5'7" 145 lbs. I have an assortment of steel tanks that I switch back and forthwith between. For OW singles, I like my Worthington HP 100' s best. I also will use a Worthington HP 130 for longer dives, but the 100's work for most.

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[DA Aquamaster]

Steel 72s are 25" tall and 6.9" in diameter. They vary a bit but on average weigh around 27 pounds empty without a valve.

X7-100s are similarly short at about 24", and when doubled, offer enough gas for 150-200 ft dives (with proper training, deco gas, etc). They also weigh only 33 pounds. The bad news is they are 3442 psi tanks. The good news is that 3000 psi in an X7-100 is still 87 cu ft. As a single tank, with a full fill, a single X7-100 gives you 23 cu ft more gas than an AL 80, but even if you only get 3000 psi in it, it is still 10 more cu ft than a full AL 80 and it weighs only 1 pound more.

Another low pressure option is the LP 95. It's 8" in diameter rather than 7.25" but it's still 24" tall. Fabers are about 38 pounds while worthington's are 42 pounds, so they are respectively a little and a lot heavier than an X7-100.

The thing to consider is that an LP 95 holds 95 cu ft at 2640 psi (the plus rated 10% overfill pressure), but only 86 cu ft at the 2400 psi service pressure stamped on the shoulder - which is all some shops will fill them to, even with a current plus rating.

So...if all you can get is a 2400 psi fill and 86 cu ft, save yourself 5 to 9 pounds of tank weight and just go with the X7-100. Even at only 3,000 psi you'll get just as much gas.

You can get a low pressure 80, but it's about the same height, diameter and weight as the X7-100 and not surprisingly, holds about the same amount of gas at a similar pressure so it's a losing proposition.

 

[TSandM]

I wouldn't go with 95s, if you are thinking about doubling them in the future. They're heavy, unbalanced beasts as doubles. The HP100s are delightful, both as single tanks and as doubles. But if you want more gas, the HP130s are great, and manageably heavy as single tanks. Only crazy Florida cave divers double them up

 

[Jim Lapenta]

I wouldn't go that far. Some NE wreck divers like em as well. As long as all I have to do is stand up and fall overboard with them. Walk with double 95's? No thanks.

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[KD8NPB]

Seems like the X7-100HP might be the way to go to go for me. The Faber version is 100 cf @ 3180 psi, so that's doable...the weight is a tad more than PST.

What about the X8-119HP by PST? It's 119 cf @ 3442 psi.

 

[DA Aquamaster]

Seems like the X7-100HP might be the way to go to go for me. The Faber version is 100 cf @ 3180 psi, so that's doable...the weight is a tad more than PST.

What about the X8-119HP by PST? It's 119 cf @ 3442 psi.

Whoa...stop the bus and get off.

The Faber 100 cu ft tank is a 3AA steel tank with a 3180 psi service pressure. It's also 5 pounds heavier than an X7-100 and most importantly, 5 pounds more negatively buoyant when full. They are in effect, boat anchors and doubling them usually results in a diver who is badly over weighted. To make it worse, you only get 100 cu ft at the 10% overfill pressure of 3498 psi. At the 3180 psi service pressure you'll only have 91 cu ft at an the same 3000 psi mentioned above, you only have 86 cu ft.

Thus it's just heavier than a Worthington X7-100 and offers no advantage over it, especially where you are concerned about fill pressure.

You need to remember that for 3AA steel tanks, the advertised capacity is based on a 10% overfill. While special permit steel tanks like the X7-100, and aluminum tanks advertise the capacity at the service pressure stamped on the shoulder (with the exception of the AL 80 which should be called the "AL 77").

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The X8-119 is very similar to the Worthington LP 95 - not bad, but not high on my list either.

I wouldn't go with 95s, if you are thinking about doubling them in the future. They're heavy, unbalanced beasts as doubles. The HP100s are delightful, both as single tanks and as doubles. But if you want more gas, the HP130s are great, and manageably heavy as single tanks. Only crazy Florida cave divers double them up

I agree with Lynn, with a minor qualification. Faber 95s are pretty pleasant as doubles, while the Worthington Coyne and PST 95's are more beaslty.

 

[halocline]

You would want the faber FX 100(blue steel) series, not the older 3AA faber as pointed out. If you just can't get a 3442 PSI fill, probably your best bet would be a faber LP95, and hope for a slight overfill. I'd get the single tank you really want and worry about doubles later. Neither of those tanks really qualify as 'big' though, and they'll hold quite a bit less gas than your double 72s.

 

[Glenn08]

If you find double steel 72's have extra air capacity, I suggest you try double aluminum 50's. I like my double 50's with a Selpac manifold that gives me 2 valves and 2 first stages. I'm 6' and I wear the tanks valves-down, which I find much easier to reach in full gear. I also like the buoyancy of the aluminum tanks. I'd rather wear lead that I can drop than have to drop steel tanks if my dry suit and / or BC fail - fortunatley only theory - so far.

 

[ams511]

What do you think of the Faber FX series?