Question 4106 Deck General

The correct answer is A) When going astern at slow speed, they provide effective steering control. Tunnel bow thrusters are primarily designed to provide enhanced maneuverability at low speeds, especially when going astern. This is due to their location at the bow, which allows them to create a lateral thrust to aid in steering the vessel. Their effectiveness is most pronounced at slow speeds, as they can help overcome the reduced rudder effectiveness that occurs when the vessel is moving astern. The other options are incorrect because: B) Bow thrusters typically do not have as much power as a dedicated tug, C) Their effectiveness can be limited at very low or very high drafts, and D) They are generally not effective at speeds above 10 knots, as the hydrodynamic forces overcome the thrust generated by the thruster.