The propeller on a vessel has a diameter of 24.6 feet and a pitch of 26.1 feet. What would be the apparent slip if the vessel cruised 462 miles in a 24 hour day (observed distance) at an average RPM of 72?

Correct Answer: Option D — -3.8%

Engine distance: (72 * 1440 * 26.1) / 6076.1 = 445.3 miles. Slip: (445.3 - 462) / 445.3 = -0.0375, or -3.8%. Negative slip occurs when the vessel's observed speed exceeds the theoretical speed of the propeller, often due to significant following seas or currents.