What is a Draft Survey?
A Draft Survey is a method of determining the quantity of bulk cargo loaded onto or discharged from a vessel by measuring the change in the vessel's displacement (derived from reading the vessel's draft marks) before and after cargo operations. It is widely used for bulk cargo such as coal, grain, ore, and fertilizers where weighing on shore is impractical.
How Draft Survey Works
Surveyors read the vessel's fore, mid, and aft draft marks on both port and starboard sides before and after cargo. Using the vessel's hydrostatic tables, they calculate the displacement at each draft. The difference between initial and final displacement equals the weight of cargo loaded or discharged.
