What is a primary function of the ship's lube oil system?

• A. Lubricate moving parts, carry away heat, and help seal and cushion bearings.
• B. Cool the engine jacket water.
• C. Generate steam for auxiliary systems.
• D. Supply fuel to the main engine.

Answer: (C)

The main idea is that the lube oil system keeps the engine’s moving parts protected and running smoothly. It provides a continuous film of oil to bearings and gears, reducing friction and wear. As the oil circulates, it picks up heat from those hot parts and is cooled, helping to keep temperatures in a safe range. The oil also helps seal clearances and cushion bearing surfaces, which smooths operation and absorbs shocks during startup and run. This combination—lubrication, heat removal, and bearing sealing/cushioning—is what the lube oil system is designed to do.

The other functions listed belong to different systems: generating steam comes from the ship’s boiler/steam plant, cooling the engine jacket water uses the jacket water cooling system, and supplying fuel is the role of the fuel system.