"Michael Daly" ) writes:

Most recreational hulls are built for stability, but advanced hulls are
made with rounded, or nearly rounded, bottoms.

Yes, I'm going to have to backtrack on the subject of circular cross
sections for kayaks. Yesterday at the river I saw a short cheap bright
yellow plastic kayak with a very round cross section, tapering toward the
ends. I was ignoring how low is the centre of gravity when a paddler sits
on the bottom of a round hull with its deeper draft. Although it's not
easy to get into such a boat, once the paddler's butt is firmly planted on
the bottom the boat is more stable. Also, the manner of paddling a kayak,
compared to paddling a canoe or using a small sail, keeps the weight
centred so the lack of reserve bouyancy is not much of a problem. It was
unstable getting into my plastic barrel canoe, and it needed sponsons to
carry sail. In addition, rolling a kayak over is not supposed to be a
problem. It's a feature.

When sailing my narrow sail-and-paddle boats I have to lie on the bottom
of the boat to lower the center of gravity and counter the heeling force
of the sail, even though both boats have a flat bottom and reserve
bouyancy. The smallest one has to have sponsons to carry sail. I've had to
make backrests for both of them to lie back on when sailing.




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