Canoes are a very old and a very basic type of watercraft. They work very well on freshwater lakes and rivers. They vary considerably in design while remaining within some general boundaries. Like airplanes, the function of a canoe determines its form. Lake canoes are designed differently than whitewater canoes. A canoe that has multiple functions will have to combine different design forms. These are the parts that you will find in all canoes.
The hull of the canoe is the basic structure. It does not include the seats, decks, thwarts, gunwales or keel. The hull is what keeps the water out of the canoe.
The ends of a canoe have two names: the bow and the stern. The bow is in the front and the stern is in the back. The two can often look almost identical, but this is not always the case. Not all canoes are symmetrical when viewed from above. An asymmetrical canoe might have a wider stern half than bow half. In most cases the easiest way to tell the stern from the bow is to look at where the seats are. The seat is closer to the end in the stern than it is in the bow. The bow is almost always pointed, while the stern can be either pointed or square.
The decks are the smaller triangular pieces in the bow and stern. The decks go between the gunwales, and attached to the stems, if the canoe includes gunwales and stems. On some fibreglass and plastic boats stems are not used. In this case the decks are still at the stern and bow, but are more commonly attached over the top of the gunwales.
The gunwales are long, thin strips of wood, aluminum or plastic that run along the top edges of each side of the canoe. They provide rigidity and strength to the edges. On traditional wood canoes there are inwales and outwales, which are glued, screwed or bolted together to form gunwales. Aluminum or plastic gunwales are usually one piece affairs.
Canoe seats span the hull from one gunwale to another. The number of seats varies, but two seats is a common number. In a traditional canoe the seats hang down from the gunwales, but in some fibreglass canoes they simply run from blocks on the hull itself. Again, the seats in the stern are usually closer to the stern than the seats in the front are to the bow. Thwarts are strengthening members that run from side to side, usually between the seats, and often right in the center of the canoe. A center thwart can also double as a carrying yoke.
The stems are the curved pieces of wood that create the curve at the bow and stern. They really only occur in traditionally built canoes. They are not often used in plastic of fibreglass boats.
If you want to simply paddle a canoe now and again you don't need to know what these parts are. If you want to build or repair a canoe then you will need to know what the parts are and understand what purpose they serve. If you know and understand the parts you will be able to design, build or repair canoes much more easily.