Posted by Murddoc on March 21, 2001 at 16:40:57:
In Reply to: Re: Am I the only one who needs lead with a steel tank? posted by Jeff B on March 20, 2001 at 19:41:59:
The reason that I chose to compare cf rather than psi is because AL tanks are filled to a higher pressure than LP Steel, therefore if both tanks were at 1000psi for example, the steel tank would have more cf remaining.
I don't have the experience as some of you and sometimes know just enough to be dangerous.
Correct me if I am wrong....The only way to increase bouyancy is to either decrease weight or increase volume (physical dimension of tank not compressed air within). The dimensions of the tank do not change, so the weight must. The only weight loss can be due to the change in the amount of air within the tank. Loosing more air would also mean loosing more weight. You have the 80cf tank loosing 7lbs while the 95 only looses 4 lbs. Air weighs approximately .076 lbs/ cf, that calculates to 6.08 lbs for the 80 and 7.22 for the 95.
I don't know the exact numbers for my tanks, so I found some numbers on the internet. For each tank size, the change in bouyancy was the same regardless of AL, HP or LP Steel.