It seems to me that, when we first start building boats we are leery of thinner plywood. We tend to go heavier for strength. Later, we learn that thin plywood (say, 1/8") glassed inside and out is strong as all get out.
A single piece bottom that is flat, may flex and "oil can". This can be readily cured with some thin reinforcing strips (again, 1/8" plywood) applied along most of the length of the bottom. These can be either inside or outside. They will stiffen up a boat's bottom considerably.
I learned a lot about hull design and construction one day in Sault Sainte Marie, Ontario. There, is the Canadian Bush Plane Museum. I have many years experience under my belt with jet aircraft, but none with simpler birds powered with reciprocating engines and props.
The fuselages of those bush planes bear a very strong resemblance to hulls of displacement watercraft (canoes and kayaks). Ribs, stringers, longerons, bulkheads, stations, etc. on aircraft all come directly from the ship building trade. The planes have a semi-monocoque construction in many cases. Some are skin on frame. Our boats are either semi-monocoque or full monocoque. A full monocoque structure gets all of its strength from the skin; an egg is a good example of a fully monocoque structure. Semi-monocoque means part of the strength from the skin, and part from internal bracing.
And, the pointy ends for forwards in both aircraft and boats.
