I usually dive in California off a dive boat. Most of the boats fill at 3000psi as the norm. My question is I would like arround 100cf of air, should I buy a LP 95 and risk the constant overfills, or buy a larger HP tank and take the short fill. Also which HP tank would give me arround 100cf when only filled to 2800-2900 psi. Thanks
LP vs HP question
- Thread starter rds912
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An HP120 - 120 CuFt @ 3442 would be 101 CuFt @ 2900. But I would buy an LP95 - Here in cave country they are regularly filled beyond 3000 MAYBE it fails hydro a time earlier than it would have everything else being equal.
Scared Silly
Contributor
I too would do the LP95. For the same reason outlined above.
cmburch
Contributor
Here is the cf comparison for different fills. Worthington X-Series SCUBA Diving Tanks
Cylinder.........2640 psi.....3000 psi.....3442 psi
X7 Steel 80......64 cu. ft......72 cu. ft........80 cu. ft.
X7 Steel 100....80 cu. ft......89 cu. ft.......100 cu. ft.
X7 Steel 120....96 cu. ft......107 cu. ft......120 cu. ft.
X8 Steel 119....95 cu. ft......107 cu. ft......119 cu. ft.
X8 Steel 130...104 cu. ft......117 cu. ft......130 cu. ft.
I like my HP100 the best overall - similar in weight to an Al80, a little shorter, and can remove 6lb from belt compared to Al80. As seen here it would be 89cf at 3000psi.
I also have HP130's - 10lb heavier than HP100. MONSTERS May be Good for boat dives if you don't mind lugging around the extra mass and bulk- use cart to get to boat. HP 120 is about 5lb heavier than Al80 but longer. XS SCUBA site has tank comparisons.
Cylinder.........2640 psi.....3000 psi.....3442 psi
X7 Steel 80......64 cu. ft......72 cu. ft........80 cu. ft.
X7 Steel 100....80 cu. ft......89 cu. ft.......100 cu. ft.
X7 Steel 120....96 cu. ft......107 cu. ft......120 cu. ft.
X8 Steel 119....95 cu. ft......107 cu. ft......119 cu. ft.
X8 Steel 130...104 cu. ft......117 cu. ft......130 cu. ft.
I like my HP100 the best overall - similar in weight to an Al80, a little shorter, and can remove 6lb from belt compared to Al80. As seen here it would be 89cf at 3000psi.
I also have HP130's - 10lb heavier than HP100. MONSTERS May be Good for boat dives if you don't mind lugging around the extra mass and bulk- use cart to get to boat. HP 120 is about 5lb heavier than Al80 but longer. XS SCUBA site has tank comparisons.
ucfdiver
Contributor
LP and a 3600psi cave fill, shhhh, don't tell anyone you're overfilling em 
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You have to more or less ignore theFlorida opinons unless shops and boats in your area will do 140% overfills on low pressure tanks.
An LP 95 is larger and heavier (or larger and a lot heavier depending on brand) than a special permit 3442 psi 100.
Looking at it differently, if you are willing to haul around the weight and bulk of a LP 95, for basically the the same size and weight you can go with a 3442 psi 120 and legally get the same gas as an overfilled LP 95 without having to rely on a shop being willing to violate DOT regs to overfill your tank.
3442 psi Special Permit tanks have essentially made LP tanks irrellevent everywhere but North Florida where overfilling is the norm. But they still have a strong following there and among those who wannabee there so it's a case of old ideas not really going way until the people that promote those ideas (like massively overfilling low pressure tanks even though its illegal, wink-wink) either retire or die.
An LP 95 is larger and heavier (or larger and a lot heavier depending on brand) than a special permit 3442 psi 100.
Looking at it differently, if you are willing to haul around the weight and bulk of a LP 95, for basically the the same size and weight you can go with a 3442 psi 120 and legally get the same gas as an overfilled LP 95 without having to rely on a shop being willing to violate DOT regs to overfill your tank.
3442 psi Special Permit tanks have essentially made LP tanks irrellevent everywhere but North Florida where overfilling is the norm. But they still have a strong following there and among those who wannabee there so it's a case of old ideas not really going way until the people that promote those ideas (like massively overfilling low pressure tanks even though its illegal, wink-wink) either retire or die.
cmburch
Contributor
I am surprised sometimes especially on hunting when Florida is giving local advice to a west coast diver in completely different conditions. I have met some experienced guys from Florida that have dived both oceans though.
I'm not talking massively overfilling, and I'm certainly not in Florida.
A "hot" 3000psi fill puts the LP95 at 2700psi. Been there, done that. I've been on quite a few California dive boats and this is very common. Even the boats with LP Steels fill theirs to 3000 psi, so my statement stands. A local captain said to us during a dive briefing, "these are low pressure 80 cubic foot tanks, but somehow they got filled to 3000 psi. Oops. If you're worried about it, bleed some pressure off before you put your regulator on."
And I don't care who you are, if you buy a high pressure 130 cubic foot tank, you're going to feel short changed when you see it "only" has 2700 psi in it.
cmburch
Contributor
Get the best tank for your needs. The new HP tanks come with Pro Valve for both Yoke and DIN connection. Some shops charge more for a HP fill. The new tanks are O2 cleaned and Nitrox ready. Also check the buoyancy characteristics and empty weight. I do not want to have more weight on my belt or be lugging a huge tank around when shore diving and hiking down cliffs. If I can have a slightly negative buoyancy when empty tank is best for me vs a slightly positive.
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