A Sea kayak is a kayak developed for the sport of paddling on the open waters of the ocean.
Typically a seaworthy small boat with a covered deck and the ability to incorporate a spraydeck.
Modern sea kayaks come in a bewildering array of materials and designs. Along with the common fiberglass, rotomoulded polyethylene and kevlar, there are more exotic materials, such as carbon fiber and Royalex, and hand-built systems, such as skin on frame (canvas, dacron or other fabric over a lattice-like framework) and "stressed skin" plywood. Designs are divided into categories based on the shape from bow to stern and on the shape of the hull in cross-section. Overall shapes are:
- Symmetrical: the widest part of the boat is exactly halfway between bow and stern.
- Fish form: the widest part is forward of the midpoint.
- Swede form: the widest part is aft (in back) of the midpoint.
- Chine: hard chine, medium chine, soft chine
- Flat bottom
- Semi-round bottom or, even, round bottom.
- Shallow V-bottom
- Combinations of the above.
