Kayaking is the use of a kayak for moving across water. It is distinguished from canoeing by the sitting position of the paddler and the number of blades on the paddle. A kayak is defined by the International Canoe Federation as a boat where the paddler faces forward, legs in front, using a double-bladed paddle. Most kayaks have closed decks, although sit-on-top and inflatable kayaks are growing in popularity as well.
Kayaks can also be classified by their design and the materials from which they are made. Each design has its specific advantage, including performance, manoeuvrability, stability and paddling style. Kayaks can be made of metal, fibreglass, wood, plastic, fabrics, and inflatable fabrics such as PVC or rubber, and more recently expensive but feather light carbon fiber. Each material also has its specific advantage, including strength, durability, portability, flexibility, resistance to ultraviolet and storage requirements. For example, wooden kayaks can be created from kits or built by hand, but they are heavy to transport. Inflatable kayaks, made from lightweight fabric, can be deflated and easily transported and stored.
"Sit on tops", as the name suggests, involve sitting on top of the kayak in an open area. "Cockpit style" involves sitting with the legs and hips inside the kayak hull with a spray deck or "spray skirt" that creates a water resistant seal around the waist. "Inflatables" are a hybrid of the two previous configurations, these boats have an open deck, but the paddler sits below the level of the deck. "Tandems" are configured for multiple paddlers, in contrast to the single person designs featured by most kayaks. Tandems can be used by two or even three paddlers.