If the speed necessary for reaching port at a designated time is 12.6 knots and the pitch of the propeller is 13.6 feet, how many revolutions per minute will the shaft have to turn, assuming no slip?

Correct Answer: Option D — 94 RPM

With zero slip, the formula simplifies to: (Knots × 6,076.1) / (Pitch × 60). Using 12.6 knots and 13.6' pitch: (12.6 × 6,076.1) / (13.6 × 60) = 76,558.86 / 816 = 93.8 RPM. Rounding to the nearest whole number provides 94 RPM, matching the examination key.