Boiler (Marine)
A Marine Boiler is equipment aboard a ship that generates steam by heating water, for a range of shipboard needs. On the great majority of modern motor ships, boilers provide auxiliary steam rather than propulsion — used for heating heavy fuel oil (to make it thin enough to pump and burn), heating cargo (on tankers), domestic hot water and accommodation heating, tank cleaning, and various engine-room services.
Ships typically have an oil-fired auxiliary boiler for use in port and at low load, and an exhaust-gas economizer that recovers heat from the main engine's exhaust to raise steam efficiently at sea (a useful energy-saving measure). On steam ships and some LNG carriers, large boilers supply steam to propulsion turbines. Boilers operate at pressure and are safety-critical, subject to regular survey and careful operation. They are maintained by the engine department under the Chief Engineer, and their reliable operation is important to fuel handling, cargo (on tankers) and shipboard services. The marine boiler is a key auxiliary system, related to the engine room, fuel system and cargo heating. It is part of the machinery that keeps a ship functioning.
Heavy fuel oil is too thick to burn until it is heated, and tanker cargo often needs warming too — the boiler provides that steam, along with heating and services. Exhaust-gas economizers even recover engine heat to raise it for free at sea. Safety-critical and surveyed, the boiler is an unglamorous but essential part of keeping fuel, cargo and the ship's systems working.
What do boilers do on a modern motor ship?
Provide auxiliary steam — heating heavy fuel oil, cargo (on tankers), hot water and services — rather than propulsion.
What is an exhaust-gas economizer?
A boiler that recovers heat from the main engine's exhaust to raise steam efficiently at sea, saving fuel.