What's the difference between a bow thruster and an APU?

• A. An APU can move 360º while a bow thruster can only move laterally (090° and 270°)
• B. Bow thruster can move 360º; APU is limited to lateral
• C. Both can move 360º
• D. Bow thruster provides vertical lift only

Answer: (A)

The main idea is propulsion versus power supply. A bow thruster is a dedicated propulsion device that creates sideways thrust to push the bow left or right in the water, commonly described as lateral movement at low speed. An APU (auxiliary power unit) provides electrical or pneumatic power to run systems or start engines; it does not propel the vessel.

Among the given statements, the one that correctly notes that the bow thruster moves laterally (port or starboard) aligns with how bow thrusters are used, while the APU’s role is power, not thrust. Keep in mind that some propulsion systems, like azimuth thrusters, can rotate and provide thrust in any direction, but a standard bow thruster itself is not a 360° directional thruster.