Am I missing something here or will my M-15 in it's present condition SINK, if filled with water?

The short anwer is Yes. However, think how difficult it would be to COMPLETELY fill the M15 with water. Even with a major breach of the hull, it would be hard to imagine an angle that the M15 could assume which would not trap at least a couple of cubic feet of air. I have never heard of any M15 becoming fully swamped, or sinking. Having said that, I am all for preparing for the worst case scenario. I once calculated that you'd need just shy of 10 cubic feet of foam to keep a fully swamped M15 afloat but this did not take into account the foam and balsa cored hull and decks, so your 8 cubic feet might be closer. On the other hand, what about the extra weight of anchors, battery, etc.? So I guess I'll stick with the 10ft3 figure. For those of you who are thinking of doing it with empty used 1-gal milk jugs, you'll need about 70 of them. -- Steve McClellan M15 #152 Chicago Area