A sea kayak is a closed-deck boat with an open area near the middle where the paddler sits. If a kayak carries one person, it's called a K-1 or a single. If it carries two people, it is called K-2 or tandem. A kayak used by Eskimos for transportation and hunting. It is also a simple, primitive and ecological vehicle that can be made from plastic, fiber or fabric. You can sail a kayak, if you have proper equipment.