If the speed of the propeller is 135 RPM, the speed of the engine camshaft shown in the illustration will be __________. MO-0003

Correct Answer: Option A — 135 RPM

Direct-drive, two-stroke slow-speed marine diesel engines operate on a single-revolution cycle where each downward stroke includes power generation. Therefore, the camshaft turns at a 1:1 ratio relative to the crankshaft and propeller speed, equating to 135 RPM for both components.