Deadweight is defined as the maximum deadweight of the ship and measure of the ship's carrying capacity. It takes into consideration the weight of the cargo on board, fuel, ballast water, fresh water, crew, provisions for the crew, excluding the weight of the ship in the calculation.
It is a measure of a ship's ability to carry various items: cargo, stores, ballast water, provisions, and crew, etc. A large part of the deadweight is used for water ballast necessary to meet stability requirements. To calculate the Deadweight tonnage figure, take the weight of a vessel that is not loaded with cargo and subtract that figure from the weight of the vessel loaded to the point where it is immersed to the maximum safe depth. Only in the case of heavy loads put at the bottom of the hold, greater deadweight translates automatically into greater amounts of cargo.