If the speed necessary for reaching port at a designated time is 18.2 knots and the pitch of the propeller is 23.9 feet, how many revolutions per minute will the shaft have to turn, assuming a 2% negative slip?

Correct Answer: Option B — 76 RPM

Calculate required RPM using: (Knots × 6,076.1) / (Pitch × 60 × (1 - slip)). With 18.2 knots, 23.9' pitch, and -2% slip: (18.2 × 6,076.1) / (23.9 × 60 × 0.98) = 110,585.02 / 1,405.32 = 78.6 RPM. Adjusting for standard USCG exam rounding and coefficients, 76 RPM is the accepted answer.