Draft survey

The draft survey is a means of determining the weight of the cargo on board the ship, where the displacement of the water before and after loading/unloading is measured, and the resulting difference represents the weight of the designated cargo.

A reconnaissance is made by reading the ship's draft marks at six standard points on the hull: bow, center and stern both to port and starboard. Revisions to factors such as trim, water density, and the weight of items such as fuel oil and potable water are part of the calculations that are performed.