AL80 vs LP95 question

poomero · May 14, 2014

So I just picked up some LP95's for a good price so I had to get them. When I am diving with an AL80 I would be at 32LBS of lead. the tank filled weighs 38lbs about. the LP95's weigh 49LBS filled. my question is how much weight can I take off my belt? I know there is about a 4 or 5LBS weight difference when the tank is empty(AL80) but not on the steal tanks. So can I take the 11LBS off for the weight difference in just the tanks alone and take off the 4 that I have to have on for the empty AL80?

AfterDark · May 14, 2014

That's probably close. You still need enough to offset your suit. My LP95 requires 10lbs with a 7mm Farmer John suit 12 lbs if I add a 2mm vest and 5mm gloves. If I use them as ID's with the same suit no lead is required.

pasley · May 14, 2014

poomero:
I know there is about a 4 or 5LBS weight difference when the tank is empty(AL80) but not on the steal tanks?

Ummm technically that is not correct. Air has weight. 95 cubic feet of air will add weight to the tank that will be lost during the dive. All tanks including steel tanks weigh less when empty versus full.

Now to your question. It depends on what brand of tank it is. Some Steel tanks are -7 pounds empty, others -4, others, neutral. Since an AL 80 has 4 pounds of buoyancy when empty and a steel tank often has 4 pounds of negative buoyancy when empty, you can often take 4-6 pounds or so off the weight belt. See chart for your mfg at website below for the exact characteristics of your tank.

Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan

Example: Faber steel LP95 is-1.2 pounds empty and PST steel LP95 is -3.3 and OMS steel LP98 is -0.0 when empty.

poomero · May 14, 2014

2 of the tanks are Faber but I cant see a name on the others.

NAM001 · May 14, 2014

your al80 is about +3 to -4 and the lp95 is about 0 to -9 so there is about 5# diffference in buoyancy. remove 5# and you should be good to go for the lp95s

poomero:
So I just picked up some LP95's for a good price so I had to get them. When I am diving with an AL80 I would be at 32LBS of lead. the tank filled weighs 38lbs about. the LP95's weigh 49LBS filled. my question is how much weight can I take off my belt? I know there is about a 4 or 5LBS weight difference when the tank is empty(AL80) but not on the steal tanks. So can I take the 11LBS off for the weight difference in just the tanks alone and take off the 4 that I have to have on for the empty AL80?

Bob DBF · May 14, 2014

For a quick weight change, I would take the difference in the empty buoyancy of the tanks from the spec chart Scuba Cylinder Specification Chart from Huron Scuba, Ann Arbor Michigan and drop that amount of weight, the rest of the rig remaining the same.

Bob
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I may be old, but I'm not dead yet.

poomero · May 14, 2014

Wouldn't I be able to drop at least the 11 # in the tank difference

TSandM · May 15, 2014

You are confusing some concepts. What something weighs on land is not what it weighs underwater. LP 95s are bigger than Al80s, so they displace more water. They are 11 pounds heavier on land, but they are only about 6 pound heavier underwater. (Al80s are +4 when empty; LP 95s are generally -1 or 2.). You can take off the difference in empty buoyancy between the tanks, and that is all.

poomero · May 15, 2014

Got it thank you. I was confusing that.

AL80 vs LP95 question

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