The speed of advance necessary to arrive in port at a designated time is 15.8 knots. The pitch of the propeller is 20.75 feet. You estimate 5% positive slip. How many revolutions per minute must you turn to make the necessary speed?

Correct Answer: Option A — 81.2 RPM

Propeller slip is incorporated using the formula Speed = Pitch × RPM × (1 - slip) × 60 / 6080. Converting 15.8 knots with 5% positive slip (factor of 0.95) and a 20.75-foot pitch yields exactly 81.2 RPM per Bowditch procedures.