Length and beam (the widest portion of the canoe at the midsection) will determine weight, carrying capacity, maneuverability, speed, and the number of people that can paddle the canoe. The freeboard (the amount of the hull that sits above the water line) is greater with longer, wider, and deeper hulls — increasing carrying capacity. Know the carrying capacity of your hull. Will it meet the load requirements for the intended use and still maintain its performance?

Depth also determines a canoe's ability to carry a load. Touring canoes (usually about 16 feet) are often 13.5 inches deep, while 17-foot expedition canoes are often 15 inches deep. Whitewater playboats (11 feet or so) are also about 15 inches deep. When loading rockered playboats and river-runners, maneuverability is more quickly lost. Flat-bottomed canoe hulls are least affected by loading, as they remain stable and slow.

The canoe's width and its effect on speed is related to length. Beam can be greater with longer boats and not adversely affect speed. Touring and expedition canoes need to maintain length-to-beam ratios so as not to compromise speed or load-carrying capacity. Sport boats tend to be wider to create stability and increase payload. A good length-to-beam ratio for a touring canoe is 16 feet to 33 inches. A good length-to-beam ratio for an expedition canoe is 17 feet to 36 inches. Whitewater playboats of 11 feet have beams of about 28 inches.