Question 82Motor Plants - QMED

The correct answer is D) 23 and 24. The main engine cooling water system is often designed with multiple heat exchangers that can be isolated and bypassed when maneuvering in or out of port to reduce the cooling water flow and allow the engine to warm up quickly. In the provided diagram, heat exchangers 23 and 24 are likely the main engine jacket water or lube oil coolers, which would be isolated and bypassed during low-speed maneuvering to allow the engine to reach optimal operating temperature more quickly. The other heat exchanger options (3, 4, 5, and 6) are likely not the main engine cooling components that are typically isolated in this scenario.