I have a 1959 OT 16' Guide canoe(it's the lightweight model). The specs say it is 12 inches deep and has a flat bottom. Mine is closer to 14 inches deep and has a round bottom. I like the way it paddles and the hull doesn't look deformed at all, so my question is, did it change shape over the years or was it made that way. The gunnels, decks and thwarts are original.