See this article
Kip, have a look at this article that explains the concepts: http://www.boatus.com/goodoldboat/stability.htm The equation is expressed in an unfamiliar way here, I believe he is saying take the cube root of [maximum beam (in inches) divided by displacement (in pounds)]. Ordinary calculators don't do cube roots, so you may need to borrow or buy a scientific calculator to do it. Your number should always be between 1 and three, usually close to 2. I found in doing calculations for my boat that the weight specifed for the boat in the literature put it over 2, but adding some weight improved the number; after adding about 700 pounds, there was no improvement. That seemed to indicate that the builder had factored in 700 pounds as the expected additional weight of passengers and cargo...
