Capacities are the ability of a vessel to carry goods, fluids, cargo, and consumables. Cargo capacities are calculated as tonnages, or may be described in terms of bale, grain, cubic meters, or tonnes. Service requirements will be determined from consumables reports, though actual capacities may exceed these requirements.
Early in the design process, capacity requirements or estimations will often be used to guide vessel size and parameters. As the hullform approaches finality, the capacities reports serve as guidelines and constraint to the tank plan and general arrangement; cargo maximization being a typical goal.