A method of cleaning tanks using oil from the ship’s cargo. COW is normally used when a tanker is discharging. Oil is taken from the tanks and pumped through a special line to fixed or semi-fixed tank washing machines where it is sprayed against all inside surfaces of the tank. This procedure removes any cargo which is ‘clinging’ to the surfaces of the tank.
A system of cleaning the cargo tanks by washing them with the cargo of crude oil during discharge