USCG Exam PracticeSingle-screw maneuvering and prop walk
Running ahead with the rudder put over, what additional force acts on the stern beyond the direct pressure difference across the rudder faces?
- A. The frictional wake accelerates flow on the high-pressure face of the rudder
- B. Propeller side force reverses direction and reinforces the rudder force
- ✓ Approximately half of the propeller's thrust is directed to that side by the rudderCorrect
- D. The suction screw current is redirected to the low-pressure side of the rudder
Why C is correct
USCG Boat Crew Seamanship Manual §10-B states that running ahead, putting the rudder over directs about half the propeller's thrust to that side — a major additional force on the stern beyond the pressure differential across the rudder faces.