Ship measurements
Ship measurements consist of a multitude of terms and definitions specifically related to ships and measuring or defining their characteristics.
Definitions
– A measure of the width of the ship. There are two types:Carlin – Similar to beam, except running in a fore and aft direction.
Complement – The full number of people required to operate a ship. Includes officers and crew; does not include passengers. The number of people assigned to a warship in peacetime may be considerably less than her full complement.
Cube – The cargo carrying capacity of a ship, measured in cubic metres or feet. There are two common types:
Displacement – A measurement of the weight or mass of the vessel, at a given draught.
, deadweight and the number of items it can carry i.e. TEU 20 ft equivalent units. Displacement is expressed in tonnes. Displacement of a ship built for the US is in long tons, Warships are shown in displacement tons or tonnes. To preserve secrecy, nations sometimes misstate a warship's displacement.
Draft or draught or – The vertical distance from the bottom of the keel to the waterline. Used mainly to determine the minimum water depth for safe passage of a vessel and to calculate the vessel's displacement so as to determine the mass of cargo on board.
Draft, Air – Air Draft/Draught is the distance from the water line to the highest point on a ship while it is loaded. Air draft is the minimum height a ship needs to pass under, while standard draft is the minimum depth a ship needs to float over.
Length between perpendiculars – The distance between where the forward part cuts the waterline and the rudder post of the ship.
Shaft Horsepower – The amount of mechanical power delivered by the engine to a propeller shaft. One horsepower is equivalent to 746 watts.
Tonnage – A number derived from any of several methods to calculate the volume or other number indicative of a ship's cargo carrying capacity.