​DIVING TASK divers will proceed underwater to the overboard discharge pipe locations and plugin wooden plugs which will block seawater going into the vessel. Thereafter the valve from inside the ship is taken out and cleaned by the crew known as skinning the valve. A surveyor will then check the valves for leaks if any. Once this is done valves are put back to close position. Divers will then unplug the wooden plug from the discharge pipe; the surveyor will recheck the valve from the inside for any leaks.