14. State requirements about the needments of the propulsion plant for independent working ability of the ship

Needments stored on the ship to permit her running in a certain time. For the marine propulsion plant, main needment is fuel. The more amount of fuel stored on the ship, the higher the independent working ability is. However, weight of the fuel stored is also component of the displacement, if the fuel stored is too much then transportation ability of the ship will be reduced. So the fuel stored should be calculated suitably with power, specific fuel consumption of the propulsion plant, the times on voyage, operation area of the ship to raise the transportation ability.

The fuel stored can be calculated according to the fuel consumption in all times of an independent voyage:

∑B = ∑ Ne.gtb.t  (kg).

Where:

- åB: Amount of the fuel consumption in all times of the voyage   (kg)

- åNe: Total power of the propulsion plant.                       (hp)

- gtb: Average specific fuel consumption of  the propulsion plant        (kg/hp.h)

- t: The times of the independent voyage.                      (h)