quick questions is there a big differnece in 100 cu ft Al vs 80 Cu ft Al or 100 cu ft
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If you are planning gas it's actually a little better. Consider that you want to reserve X cubic feet as your end of dive reserve. this probably does not change making the whole 33 cubic feet bonus time.
For the AL80 the common 500 PSI is just under 13 cubic feet, so 77.4-13= 64.4 cubic feet available for the dive
100 - 13 = 87 cubic feet available for the dive (@390 PSI)
That's a 35% increase in bottom time.
Keep in mind though that going below 500 may not be in favor and you are beginning to encroach on that portion of the reserve left for gauge inaccuracies.
I agree the AL100 is a miserable turd of a tank but in a rental situation take what they have. The HP100 is a swell one to own.
If you are anew diver you will probably improve considerably but the 100 is a reasonable purchase in any extent.
Pete
For the AL80 the common 500 PSI is just under 13 cubic feet, so 77.4-13= 64.4 cubic feet available for the dive
100 - 13 = 87 cubic feet available for the dive (@390 PSI)
That's a 35% increase in bottom time.
Keep in mind though that going below 500 may not be in favor and you are beginning to encroach on that portion of the reserve left for gauge inaccuracies.
I agree the AL100 is a miserable turd of a tank but in a rental situation take what they have. The HP100 is a swell one to own.
If you are anew diver you will probably improve considerably but the 100 is a reasonable purchase in any extent.
Pete
Last edited:
ianr33
Contributor
Them
Contributor
I've only used two types of tank... rented AL80s and my HP100.
I like my HP100. I would (may) buy another. No plans to buy any aluminum cylinders, at least not in this size range.
In practice it is more like a MP90 though. I have had my HP100 filled 10 times now and have never seen a final pressure above 3100psi at 80f (in the water). Hot fills and compressors that max out at 3300 seem common.
I like my HP100. I would (may) buy another. No plans to buy any aluminum cylinders, at least not in this size range.
In practice it is more like a MP90 though. I have had my HP100 filled 10 times now and have never seen a final pressure above 3100psi at 80f (in the water). Hot fills and compressors that max out at 3300 seem common.
At 6'7", I find the AL100 to sit happily on my back. Its such a cute little tank.....
Slmason.72
Contributor
Good luck with that. Me and a buddy requested 100s on a recent blackbeards trip, didn't happen. (my buddy was an air hog and Im not one to turn down extra air). The DM was great about giving us a bit of extra fill, usually about 3300 (topping them off after they had cooled) and the best part was, he and the boat captain worked with my friend and got his SAC rate down (simlar to what E8armydiver discussed) comparable with mine and actually better on a couple of dives. (.40-.50 depending on the amount of exertion)
Really?
Oops. Misplaced the decimal point. 0.292 would be correct, which is what I indicated in my original post. What I actually did was jump a step to show that it was 29.2%.
Be very careful with changing your weight between the two tanks. The Al100 is only one pound less positive than the Al80, when empty; the reason you feel more negative with it is because of the extra gas you are carrying, and when that's gone, you're going to be buoyant again.
You don't say where you are, but if you are diving in the UK, the HP100 is a very nice tank. Being negative when empty, it WILL allow you to take several pounds off your belt, and it is quite a useful amount of gas.
Renting, you do what you can. But rather than cope with a beast of a tank, it would probably be more productive to work on why your gas consumption is higher than anyone else's.
You don't say where you are, but if you are diving in the UK, the HP100 is a very nice tank. Being negative when empty, it WILL allow you to take several pounds off your belt, and it is quite a useful amount of gas.
Renting, you do what you can. But rather than cope with a beast of a tank, it would probably be more productive to work on why your gas consumption is higher than anyone else's.
You are not going to see to much diference in your botom time with the 100 Al and the 80 Al, HP means that hey can support more presure that the other so you are going to have more presure and more Cubic Foots, but also consider that with more experience that you are going to have your are gonna start use less air, so my conclusion its.... you want a big tank for a few monts year, or a tank for the next 20 years.
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