Displacement,Deadweight & LIGHTWEIGHT
Displacement
This is the equivalent mass of sea water (sg = 1.025) displaced by the hull. It is therefore equal to the Total weight of the vesselDeadweight
Deadweight is the difference in tonnes (1000Kg) between the displacement of a ship in water of specific gravity 1.025 at the load waterline corresponding to the assigned summer freeboard and the lightweight of the ship.It includes bunkers and other supplies necessary for the vessel to proceed on passage as well as cargo.
The Deadweight may be quoted at the design draught although this would be specially denoted
Lightweight
Lightweight is the displacement of a ship in tonnes without cargo, fuel, lubricating oil, ballast water, fresh water and feedwater in tanks, consumable stores, and passengers and crew and their effects. Thus
DISPLACEMENT = DEADWEIGHT + LIGHTWEIGHT
DISPLACEMENT = DEADWEIGHT + LIGHTWEIGHT