Question 11 AEL01 - Assistant Engineer - Limited

The Correct Answer is A. **Why Option A ("bedplate") is correct:** In large, modern, slow-speed, two-stroke marine diesel engines (like those used on ships), the engine structure is built modularly from the bottom up. The **bedplate** is the lowest structural component of the main engine. Its primary function is to support the entire weight of the engine and to act as the main foundation. Critically, it incorporates the main bearings, which are the journals that house the **crankshaft**. Therefore, the bedplate is the part of the engine structure that houses the crankshaft and supports the heavy dynamic loads produced by the engine. **Why the other options are incorrect:** * **B) sump:** The sump (or oil pan) is the container located beneath the crankcase/bedplate that collects the lubricating oil. While it is related to the bottom of the engine, it does not structurally house the crankshaft; its function is storage and collection of oil. * **C) cylinder block:** The cylinder block (or entablature) sits much higher in the engine structure, above the scavenge air box and sometimes resting directly on the A-frames/columns. It houses the cylinder liners, which form the combustion space, not the crankshaft. * **D) frame:** "Frame" is a general term. While components like A-frames or columns (which connect the bedplate to the cylinder block) are crucial structural elements, they do not directly house the crankshaft. The specific component housing the crankshaft is the **bedplate**.