: What is tumblehome ?
on a canoe it means that the gunwhales are narrower than the widest point of the hull. that should explain how it would be measured. it's usually found on wider boats and aids in reaching over the side for paddling. if tumblehome is too pronounced final stabillity can become poor. i've yet to hear about tumblehome in kayaks, but i'm a bit new to the better boats
hope this helps;
daren.....