USCG Exam PracticeTwin-screw vessel handling
On a twin-screw vessel, a coxswain wants to hold a course while a steady wind is pushing the bow to leeward. Without using the helm, which throttle adjustment is appropriate?
- A. Reduce RPM on both engines equally to decrease leeway.
- ✓ Increase RPM on the leeward engine above that of the windward engine.Correct
- C. Increase RPM on the windward engine to match the leeward engine.
- D. Clutch the leeward engine astern while holding the windward engine ahead.
Why B is correct
To counteract wind pushing the bow to leeward, the coxswain turns the leeward engine at higher RPM than the windward one until the pressure comes off the helm, using asymmetric thrust to maintain course. (USCG Boat Crew Seamanship Manual §10-D)