Native kayaks like the one shown in the picture from Nunivak above were the forerunners of the modern sea kayaks we use today. While they share similar shapes and purposes, little else is similar in their construction, stability, or safety. Generally, sea kayaks are longer and more tapered at the ends compared to their river cousins. A touring sea kayak will be around sixteen feet (4.9 meters) long and have a beam of about 25 inches (63.5 centimeters). Most kayak safety experts recommend using a sea kayak that is at least thirteen feet (4 meters) long.
Construction – Native kayaks used a framework to support the skin used to form the hulls of their craft. Except for folding kayaks, modern sea kayaks use materials that require no internal framework to function. Building materials come in two classes, composites and plastics:
- Composites – These are laminated material like fiberglass, carbon fiber and Kevlar bonded together with polyester or epoxy resin. Composite kayaks are expensive and subject to abrasion on barnacle encrusted, rocky beaches. They are however much lighter in weight.
- Plastics – Plastic kayaks are roto-molded, that is, formed in slowly spinning molds that shape them. Common plastic materials used in kayaks are linear polyethylene and cross-linked polyethylene. Cross-linked polyethylene is the tougher of the two choices and hold up well in rough beach conditions. Plastic kayaks will weigh more than ten pounds (4.5 kilograms) than a similarly shaped composite craft.
Positive Flotation – Modern sea kayaks are designed with watertight flotation compartments and unused voids in the hull are often filled with foam. Chambers installed forward and aft of the cockpit have watertight hatches and are used to store gear. A touring kayak can easily carry camping equipment and food for a week or more.
Kayak Cockpit – The paddler sits low in the kayak cockpit. Sea kayaks are designed so that the paddler is near the bottom of the hull, which keeps the center of gravity low and improves the stability of the craft. The cockpit has a combing or lip around it to facilitate use of a spray skirt/paddle jacket to keep out water. Many cockpits will have thigh braces that help stabilize the paddler within the kayak. Rudder pedals are located inside the cockpit. There is usually room in the cockpit for a water bottle, a small dry sack and emergency gear like a marine VHF radio.
Deck Fittings – Sea kayaks have a number of important features associated with their decks.
- Lifting Toggles – These are handles usually formed of plastic that are attached to each end of the kayak with a short piece of cord.
- Deck Bungies – There are bungies installed forward and aft of the cockpit that allow readily accessible gear to be carried on the deck. This can be a spare paddle, a bilge pump or a chart.
- Compass – Many sea kayaks have a magnetic compass mounted into the combing forward of the cockpit. Learning to use a chart and compass is an important seamanship skill. They make excellent backups for a GPS receiver with a dead battery.
- Watertight Hatch Covers – Watertight compartments will have hatch covers in place to prevent entry of water. Many hatch designs use a neoprene cover that fits under the hatch itself. Hatch covers are usually held in place with nylon straps and buckles.
- Rudder Tripping Line – Kayaks equipped with a rudder will have a line running up near the cockpit that allows the paddler to raise and lower the rudder. It is a good practice to raise the rudder before beaching a kayak.
- Life Line – Some sea kayaks will have a line running around the outside edge of the deck that provides a grab point for a person in the water reaching for the kayak.