Question 162General Subjects - 1st Asst/Chief

The correct answer is C) Controllable-pitch propeller. Tunnel bow thrusters often use controllable-pitch propellers to limit the starting current of the single speed drive motor. This is because controllable-pitch propellers allow the pitch to be adjusted, which enables the thruster to produce the necessary thrust without drawing an excessively high starting current from the electric motor. The other options, such as cycloidal, detachable-blade, and fixed-pitch propellers, do not offer the same ability to adjust the pitch and manage the starting current.