The deck must have sufficient camber, or curvature, to accommodate the paddlers knees, feet, and gear. A kayak with a cambered or peaked forward deck is easier to Eskimo roll. However, decks that are too high increase windage and make the boat more difficult to handle in extreme weather conditions and high aft deck may hinder leaning back to roll. A few plywood kayak decks are composed of flat, as opposed to cambered, sections. Most are designed with the mistaken belief that they are easier to build than curved decks.
Cambered decks are often simpler to construct and are usually lighter and stronger.
Cockpits and seats can be customized by gluing in closed-cell foam padding. The cockpit opening should allow the paddler to enter and exit the boat quickly and efficiently. However, it must not be so wide or long that the paddler can't brace his or her knees under the deck. A key-hole shaped cockpit is often used because it can be long enough to allow easy entry and exit while still providing a place to brace one's knees. A sea kayak's coaming must be strong enough and low enough to sit on when performing a wet reentry.