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easyrider003
01-29-2008, 17:44
Right now I am diving a 80al tank, 3 mil full suit, boot, gloves, and hood (all the same thickness) I am probably gonna buy me another tank sometime in the near future. From what I have read in some of the other post it seems like a steel tank is the way to go. My question is, if I swapped how much weight would I need to drop out of my BC? I am a fairly big guy. About 220lbs 5'11". I am using 8 pounds right now which is perfect/ How much weight could I drop using the steel tank? And last would you recommend using a 100 steel over an 80 steel tank?

in_cavediver
01-29-2008, 18:46
Right now I am diving a 80al tank, 3 mil full suit, boot, gloves, and hood (all the same thickness) I am probably gonna buy me another tank sometime in the near future. From what I have read in some of the other post it seems like a steel tank is the way to go. My question is, if I swapped how much weight would I need to drop out of my BC? I am a fairly big guy. About 220lbs 5'11". I am using 8 pounds right now which is perfect/ How much weight could I drop using the steel tank? And last would you recommend using a 100 steel over an 80 steel tank?

Its actually very easy to calculate. This link shows you a list of tanks and their buoyancy characteristics. We care about the empty buoyancy number (Luxfer 80 is 4.4)

http://www.huronscuba.com/equipment/scubaCylinderSpecification.html

In the case of going from from an AL 80 to a PST E7-100. We first determine the buoyancy of the tanks, the 80 is +4.4 and the 100 is -1lb. To get the net effect, simply subtract the old tank from the new tank or (-1) - 4.4 which gives -5.4 or you can drop 5.4lbs. The E7-80 is -2.5 so it would allow you to drop 7lbs of lead. Each tank can be different so be sure to match the tank you intend to buy. (The faber 100 is -7.25lbs whereas the PST 100 is -1lbs)

SarahBella
02-03-2008, 14:21
I was able to get into the pool at the Y last week and I tried out my New steel tank(-3 empty, -9 full) and I was able to sink at the start of the dive with 10 less than normal...Keep in mind I did not have my hood or goves on. We ran out of time so I was unable to do a boyancy test with 200psi left in the tank. Definitly next time though. I would expect to drop 6 or 7 lbs of lead in full gear at our next outing.

cummings66
02-03-2008, 22:54
Just be sure you're not dropping weight based on the starting negativity of the steel tank. That would be a mistake. The thing about steel tanks is you start the dive more negative than with an al tank, so you may think you need less weight than you really need, although a safe average is 6lbs. You may find the example numbers listed above to be right, but tell me, where you gonna find a 7 lb lead brick to drop? You'll either try dropping 6 or 8 and hope you was a bit heavy if you try 8. 6 is a safe bet for many steel tanks.

Jipps
02-04-2008, 10:24
when i switch to a steel tank i drop 4 pounds. And at your height you could use either the steel 100 or the 80 comfortably, personally i like the steel 100s because i like having all that air to give me longer bottom times while im hunting.