There has to be somebody on here who has a answer to this.
Is there really a sigificant difference in how a beachcat floats on saltwater vs freshwater? From a brief google search there is a 2 lb difference in a cubic foot of water. That can't add up to much for how high the boat rides.
It's not 2lb per cubic foot - more like 2% to 2.5%. A cubic foot of fresh water weighs about 62.4 lbs (28.3Kilo). A cubic foot of salt water weighs about 63.96lbs (29.0075).
This is significant if you are composed mostly of water (humans) and can make the difference of sink or swim for an egg...but doesn't have much difference on a lightweight catamaran.
Doing some really rough numbers; a cat that weighs 400lbs (sorry, I'm stopping the metric conversions) is going to get about 10 lbs of additional buoyancy in saltwater over fresh. spread out over the waterline length of two 18' hulls (roughly 12" wide at the waterline) will result in the boat floating .053 inches higher in the water...just under 1/16". Add some ripples and you'll never be able to measure the difference.
However, given the error in my approximation of the catamaran hull being square and the quick and dirty numbers, I would say the range would be between 1/16" and 1/8".
Man...you made me do algebra on a Friday...that's cold. <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />
