Performance Terms Realting to Kayaks but not necessarily specific to Kayaks
BEAM - Width of kayak. (See "Considerations When Buying" link for more detail.)
DISPLACEMENT - The weight of the water displaced by the kayak. It is equal to the combined weight of the kayak, gear, and paddler.
DRAFT - The depth of water a kayak can travel over without hitting the bottom. Draft is the deepest point of the kayak below the waterline, measured with the kayak floating at its design waterline which is a midrange of the kayak's capacity. The draft may increase up to two inches from the listed value when the canoe is fully loaded.
KEELING MOMENT - The force attempting to tip a kayak. (Also called heeling or tipping.)
INITIAL STABILITY - The measure of a kayak's resistance to a small amount of tipping from the upright position. (See the "Stability" link for more details.)
LENGTH OVER ALL - Full length of the kayak including overhangs.(See "Considerations When Buying" link for more detail.)
MANEUVERABILITY - The ability to maneuver in the water. A kayak with a lot of rocker (like a rocking chair) can be turned easier than a similar kayak with a straight keel.
OVERHANG - The part of the bow and stern that extends beyond the end of the waterline.
RIGHTING MOMENT - The force trying to keep a kayak upright. It is a measure of stability.
ROCKER - It is the amount the ends of the hull are curved upward in relation to the centre of the hull. (See "Considerations When Buying" link for more detail.)
ROLL - Side to side motion on a kayak as opposed to pitch, the fore and aft movement.
PITCH - The rising and falling of the bow and stern of a kayak; a fore and aft motion as opposed to roll.
SECONDARY STABILITY - The measure of a kayak's resistance to continued tipping throughout a roll. If you can lean your kayak over without it rilling over it is said to have good secondary stability. (See the "Stability" link for more details.)
SINKAGE (aLSO CALLED: Pounds-per-inch-immersion) - The amount of weight required to sink a kayak an additional inch.
STABILITY - The tendency for the kayak to stay upright. (See the "Stability" link for more details.)
TRACKING - The ability to paddle in a straight line. A kayak that tracks well (little or no rocker) will not be pushed off course easily by wind and waves. (See "When Buying" link for more detail.)
WATER LINE BEAM - Maximum width of kayak where kayak intersects water at designed draft.
WATERLINE LENGTH - The length of the kayak actually in the water.
WEATHERCOCK - Tendency of a kayak to turn into the wind.
WETTED SURFACE - The area of the kayaks surface actually making contact with the water.
VOLUME - The amount of cubic feet within a kayak. "High volume" does not mean much unless you know where that extra volume is located. Most kayaks can carry all the gear you would need for an extended trip. Compared to a back pack they have much more space for storage. (See "When Buying" link for more detail.)
PRISMATIC COEFFICIENT - Describes the "fineness" of the hull. It is determined by calculating the volume of the immersed hull and dividing it by the volume of a imaginary rectangle having the length of the kayak's waterline and a width of the kayak's waterline beam. (As an example a barge would have a prismatic coefficient of 90% or more, a canoe about 60% and kayaks anywhere from 45 to 58%.)