The propeller on a vessel has a diameter of 23.7 feet and a pitch of 24.8 feet. What would be the apparent slip if the vessel cruised 442 miles in a 23 hour day (observed distance) at an average RPM of 89?

Correct Answer: Option A — +11.8%

Engine distance: (89 * 60 * 23 * 24.8) / 6076.1 = 501.1 miles. Slip: (501.1 - 442) / 501.1 = 0.1179, or +11.8%. Positive slip indicates the propeller is not achieving its full theoretical distance, a common occurrence when a vessel faces significant resistance or adverse environmental conditions.