It refers to the maximum weight of goods that a ship can carry, also known as loading tonnage, that is, the difference obtained by subtracting the weight of fuel, fresh water and other reserve items that need to be stored during the voyage from the total load of the ship. Ship deadweight tonnage can be used for cargo statistics; As the basis for calculating the monthly rent of time charter; Indicates the carrying capacity of the ship; It can also be used as a unit for calculating the cost of new ships and the price of old ships.