Motor Plants & Auxiliary Boilers USCG Question #950 (Set 20)

With a direct drive main propulsion arrangement, what statement is true?

Official USCG Answer & Rule Citation

Correct Answer: Option C — The engine speed is equal to the propeller shaft speed.

Direct-drive marine propulsion setups couple the crankshaft directly to the tailshaft without reduction gearing, establishing a rigid 1:1 speed ratio where engine RPM equals propeller shaft RPM.

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