Question 57 GLI01 - Master-Unlimited Tonnage

The Correct Answer is A. **Explanation of Option A (Correct):** When maneuvering a vessel to stop and anchor, putting the engines astern (reverse) generates a powerful thrust intended to counteract the vessel's forward momentum. The resulting flow of water (backwash or prop wash) is pushed forward along the hull. When the vessel is still making headway (forward motion), the vessel is moving faster than the backward flow of the water, and the backwash is forced away from the hull. As the vessel slows down and approaches a complete stop relative to the water, the backwash is no longer overwhelmed by the vessel’s speed and begins to move freely up the sides of the hull, often reaching the amidships area or even slightly forward of the stern. Visually observing the moment the backwash reaches or passes the amidships point is a reliable, instantaneous, and practical indication, particularly for bridge watchkeepers, that the vessel has lost its forward way and is stopped or just starting to move slightly astern. **Explanation of Other Options (Incorrect):** * **B) An azimuth bearing on the beam remains steady:** While observing bearings is crucial for determining the overall movement relative to the ground (Set and Drift), an azimuth bearing on the beam remaining steady means the vessel is maintaining a constant distance perpendicular to the object being observed. This does not necessarily confirm that the vessel has stopped making *way* through the water (which is the goal of putting the engines astern). Furthermore, the steadying of a bearing often happens *after* the vessel has stopped making way and is establishing its position, or could occur if the vessel is swinging (yawing) but maintaining its distance from the fixed point. * **C) The ship's Doppler log reads zero:** A Doppler log measures speed through the water (STW). While a zero reading theoretically means the vessel has stopped making way, Doppler logs often have limitations or delays at very low speeds (creeping speeds) and may not be as instantaneously responsive or as reliable for the immediate, critical assessment of "stop moment" required during the anchoring procedure as the direct visual confirmation of the prop wash. It is used for confirming the speed, but the visual cue (A) is the primary maneuver indicator used by pilots and masters in this specific scenario. * **D) All of the above:** Since options B and C are not the *primary* and most practical indicator for confirming the instant stop during the astern maneuver, this option is incorrect.