Question 51 GLI02 - Mate of Unlimited Tonnage

The Correct Answer is C ### Why Option C (The vessel's displacement) is correct: The rate at which a vessel's speed through the water decreases after the main engine power is significantly reduced or stopped (without backing) is fundamentally governed by inertia and resistance. **Displacement** is the primary measure of a vessel's mass (or inertia). A greater displacement means the vessel has significantly more kinetic energy stored (momentum) at a given speed. This large amount of inertia resists changes in velocity. Therefore, a heavier ship requires a longer period and distance for the water resistance (drag) to overcome the forward momentum, resulting in a slower rate of speed decrease. ### Why the other options are incorrect: * **A) The number of propellers:** While the design and efficiency of propulsion affect how quickly a vessel *accelerates* or how efficiently it maintains speed, the number of propellers has a negligible direct impact on the rate of deceleration once power is removed. Deceleration is dominated by hull characteristics (resistance) and mass (displacement). * **B) The sea state:** Sea state (waves, wind) certainly *affects* the overall speed made good over the bottom, and poor sea states can slightly increase hull resistance, thereby accelerating deceleration. However, compared to the inherent inertia defined by displacement, the sea state is a secondary, variable factor. Displacement is the foundational, constant factor determining the rate of momentum loss. * **D) The vessel's horsepower:** Horsepower determines how quickly the vessel can *overcome* drag and accelerate to speed. Once the power is removed, the horsepower becomes irrelevant. The mass (displacement) the horsepower was pushing is what determines how long the vessel coasts.