Posted by Jim on October 05, 1998 at 13:46:26:
In Reply to: building a steel pontoon work barge posted by Peter carlich on October 03, 1998 at 12:49:29:
There's no fancy formula, just the density of water at 62.5 pounds per cubic foot.
What you need to do is estimate the dry weight, in pounds, of the whole rig, including people, tools, cargo and maybe some water that managed to leak in. BE CONSERVATIVE! Your life could depend on the reserve bouyancy you should design into it.
Now divide that weight by 62.5 to obtain the cubic feet of water you'll have to displace to stay afloat. Then, since it's a rectangular barge, it's easy to figure where the water line will end up - at the point where the volume under water equals the computed displacement.
US Power Squadron has a very informative booklet about boat design, I bought one at Boater's World. Opened my eyes on balance issues!
Have a marine architect look at your plans.