Old Nick wrote:

(2) If turning sharply, the boat could be a bit sluggish. The ends
need to be slim.

That's a very good point. Edging the boat would not lift the ends clear
of the water. Rather, they would dig in, probably making the boat harder
to turn than if it was on an even keel. They would also add drag
whenever the boat is edged or leaned or the water is uneven.