USCG Exam PracticeTwin-screw vessel handling
A coxswain on a twin-screw vessel notes that the single-screw compound maneuvering technique described in §10-E achieves results similar to the twin-screw twist. Which statement correctly identifies the fundamental difference between the two techniques?
- A. The compound maneuver uses only propeller side force astern, whereas the twin-screw twist uses only discharge current ahead
- B. The twin-screw twist requires pre-established sternway, while the compound maneuver does not
- ✓ The compound maneuver relies on rudder deflection and alternating thrust bursts because asymmetric or opposed propulsion is unavailable on a single-screw vesselCorrect
- D. The compound maneuver is effective only when the pivot point is aft, which is why it is initiated with a burst astern
Why C is correct
§10-E states directly that a single-screw vessel never has asymmetric or opposed propulsion available, so the coxswain substitutes by combining rudder position with alternating short bursts ahead and astern to walk the boat around — the compound maneuver. §10-D confirms the twin-screw twist uses opposed propulsion. The other options attribute characteristics to each technique that are not supported by the source text.