Three hours. Ocean-going ships have a special diesel engine with independent oil supply system, which can work continuously for 3 hours, and the submarine valve is outside the engine room. Marine diesel engines shall also have the capacity of 1 10% rated power for continuous operation1h. Ocean-going ships refer to ships that are approved to participate in the operation of international routes and engage in ocean transportation. These ships belong to one kind of inbound and outbound ships. When participating in inbound and outbound activities, they are subject to customs supervision, and the inbound and outbound articles carried by their crew members will be treated as ocean-going ships by the customs.