this is a good discussion, here's a couple of files/links that deal with the subject in depth.
Randy Watkins M15#194 >>> [EMAIL PROTECTED] 01/02/02 08:17AM >>> According to my calculations -- (somebody else check it!) -- you'd need to displace about about 12.5 cubic feet of water to float an M15 -- or a bit over twice that for the M17. Now, if we don't take into account a whole bunch of other variables, like how much water the fiberglass walls and other materials in a submerged boat would displace on their own--or the weight of the foam itself, you would need about 13 cubic feet of foam to ensure a fully water-filled M15 would float. Now, that doesn't take into account the weight of your extra large battery, anchors and other gear. On the other hand, it doesn't take into account the fact that it is extremely unlikely your hull could ever be COMPLETELY filled with water (i.e., no air pockets), so maybe we can let all the other variables slide, and just say that you want about 13 cubic feet of foam. Seems like a lot. Doesn't seem like you could get that much volume of foam just by filling really inexcessible areas with it. Does anybody have that much foam in their M15? That would take 90 1-gallon milk jugs or 351 1-liter plastic bottles. I'm going to take a really wild guess and say that it would take in the neigborhood of 50 to 100 bucks worth of Great Stuff. _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
Buoyancy Consider buying a boat fitted with in built buoyancy or have extra buoyancy installed. Many smaller boats are built with buoyancy and are said to have positive flotation. This is a technical term meaning the boat will stay upright when filled with water and will support the weight of passengers, equipment and the motor. In built buoyancy is also possible in larger fiberglass boats however it must be requested before manufacture. The benefits of buoyancy are: * the boat will stay afloat when capsizing or swamping happens * passengers can stay with the boat until help arrives * provides shelter and gives more time to activate emergency procedures if the boat stays upright, it provides an opportunity to bail water out of the boat. ( an excellent web site which discusses adding flotation to a C22 ) http://sites.netscape.net/tedsailingpage/Floatation.html
