A sea kayak is a type of watercraft specifically designed for use on the sea. The boat itself is very narrow and usually fairly long in relation to the person using it, and the sea kayak is likely to feature a rudder used for steering in choppy water. Modern sea kayaks are made of fiberglass and are much longer than whitewater kayaks, which are designed to be quick and maneuverable on narrow river passages. The user sits inside the enclosed boat, and is often surrounded by a spray skirt to keep water out of the boat and off the body.
The main propulsion source of a sea kayak is a handheld paddle, which is also usually made of fiberglass. The paddle is lightweight and buoyant so it can float should the user lose control of it. The sea kayak is steered using a rudder mounted at the rear of the boat; this rudder is controlled by foot pedals within the boat that are connected to a series of ropes that run through pulleys. Pressing one foot pedal turns the boat in one direction, and pressing the other pedal turns the boat in the opposite direction. This is a different steering method than rudderless whitewater kayaks that must be steered solely with the paddle.
The design of the sea kayak derives from traditional Aleutian models. These traditional boats were made from driftwood, bone, and seal skins, and they were exceptionally lightweight. The narrow design of the boat allows the craft to move quickly through the water, and it also makes the boat maneuverable and nimble. Modern versions can be made of fiberglass or even wood, though wood boats do tend to be somewhat heavier. Traditional kayaks were used for fishing and transportation, while many modern sea kayak models are designed specifically for recreation.
Some features of the sea kayak make it far more comfortable for longer boat trips than other types of boats. The sitting position can help keep a person's back straight, and almost all sea kayaks feature some sort of comfortable seat for resting one's weight during the trip. The sea kayak is much longer than a whitewater kayak, thereby allowing a user to extend his or her legs for a more comfortable sitting position not possible in the shorter whitewater craft. Elastic netting mounted in front of and behind the user allow for the stowage of waterproof bags or other items as well.