A kayak (sometimes generalised as a canoe) is a small human-powered boat that traditionally has a covered deck, and one or more cockpits, each seating one paddler who strokes a double-bladed paddle. The cockpit is covered by a spraydeck (skirt) that keeps the inside of the boat (and the paddler's lower body) dry. The spraydeck or similar waterproof covering attaches securely to the edges of the cockpit, preventing the entry of water from waves or spray, and making it possible, in some boats, to roll the kayak, capsizing and righting the boat without it filling with water or ejecting the passenger. Some modern kayaks have modified the traditional design in a variety of way, such as eliminating cockpits, seating the paddler(s) on top of the boat, having inflated air chambers surrounding the boat, and replacing paddles with other propulsion methods.
Kayaks are generally differentiated from canoes by the sitting position of the paddler and the number of blades on the paddle. In a kayak the paddler faces forward, legs in front, using a double bladed paddle. In a canoe the paddler faces forward and sits or kneels in the boat, using a single bladed paddle.