To float on the water, an object must be subjected to buoyancy equal to its own gravity.

So the displacement is equal to the weight of the ship, and the unit is generally "tons".

Displacement is an important parameter to measure the size of a ship.

The further breakdown is as follows:

1. Full load displacement

It is the limit of the ship's weight within the maximum buoyancy range. The specific value of a class of ships is estimated by the classification society. For warships, it is entirely up to the military to decide.

2. Load displacement

Transporting goods, personnel, fuel and materials needed for navigation. This is the draft of the hull, which should be just above the waterline.

3. Standard displacement

The displacement of the ship in the waiting state includes all crew members, food and fresh water, carrying all equipment and ammunition, and the machine is ready to start. In short, it includes everything you need to go to the war zone, except fuel and pipeline circulating water.

4. No load displacement

It does not carry goods, fuel, ammunition, personnel and materials. It only includes the circulating water in the pipeline.

5. Normal displacement

A rarely used term that only carries two-thirds of supplies and supplies.

There is no way to weigh the ship directly, and the volume below the waterline can be calculated. This calculation is called "design displacement". However, detailed technical drawings and computer calculation of ship hull lines are needed, and the results are quite different from the actual ones.