You are turning 90 RPM, with a propeller pitch of 24 feet, and an estimated slip of -3%. What is the speed of advance?

Correct Answer: Option C — 21.9 knots

Speed of advance is calculated using the formula: SOA = (RPM × Pitch × 60 × (1 - Slip)) / 6076.1. With 90 RPM, 24-foot pitch, and -3% slip (1.03), the calculation yields 21.9 knots. Negative slip indicates the vessel is moving faster than the theoretical propeller speed due to hydrodynamic factors.