USCG Exam PracticeTwin-screw vessel handling
Why does a vessel with a waterjet propulsion system have no propeller side force?
- A. The waterjet shaft is horizontal, eliminating unequal blade pitch angles
- B. The impeller rotates in the opposite direction to a conventional propeller
- ✓ The impeller runs fully enclosed in the pump housingCorrect
- D. The waterjet discharge current acts symmetrically on both sides of the hull
Why C is correct
§10-A explicitly states that a waterjet has no propeller side force because its impeller runs fully enclosed in the pump housing. The source does not attribute the absence of side force to shaft angle or discharge symmetry.