text: Width (beam): a wider boat provides more stability at the expense of speed. A canoe cuts through the water like a wedge, and a shorter boat needs a narrower beam to reduce the angle of the wedge cutting through the water. Canoe manufacturers typically provide three beam measurements: the gunwale (the measurement at the top of the hull), the waterline (the measurement at the point where the surface of the water meets the hull when it is empty), and the widest point. Another variation of the waterline beam measurement is called 4" waterline, where the displacement is taken into account. This measurement is done at the waterline level when the maximum load is applied to the canoe. Some canoe races use the 4" waterline beam measurement as the standard for their regulations. In races, the measurement is done by measuring the widest point at 4" (10 cm) from the bottom of the canoe.
  Freeboard: a higher-sided boat stays drier in rough water. The disadvantage of high sides is extra weight, extra wind resistance, and increased susceptibility to cross-winds.
  Stability and immersed bottom shape: the hull can be optimized for initial stability (the boat feels steady when it sits flat on the water) or final stability (resistance to rolling and capsizing). A flatter-bottomed hull has higher initial stability, versus a rounder or V-shaped hull in cross-section has high final stability. The fastest flat water non-racing canoes have sharp V-bottoms to cut through the water, but they are difficult to turn and have a deeper draft, which makes them less suitable for shallows. Flat-bottomed canoes are most popular among recreational canoeists. At the cost of speed, they have a shallow draft and more cargo space, and they turn better. The reason a flat bottom canoe has lower final stability is that the hull must wrap a sharper angle between the bottom and the sides, compared to a more round-bottomed boat.
  Keel: an external keel makes a canoe track (hold its course) better and can stiffen a floppy bottom, but it can get stuck on rocks and decrease stability in rapids.