Question 67 GLI01 - Master-Unlimited Tonnage

The Correct Answer is D **Explanation for Option D (Correct):** A Very Large Crude Carrier (VLCC), typically exceeding 100,000 DWT (Deadweight Tonnage) and often reaching 300,000 DWT, is an enormous mass of inertia. Even a powerful engine generating 30,000 Shaft Horsepower (SHP) is relatively small when compared to the massive displacement of the vessel. The **power-to-weight ratio** (SHP per DWT) is very low. This low ratio means that the engine power is barely enough to overcome the massive inertia and hydrodynamic drag quickly. * **Slow Response:** A small change in propeller RPM takes a significant amount of time and energy to produce a noticeable change in the velocity of the colossal mass. * **Less Stopping Power:** When the engines are reversed (Full Astern), the low power-to-weight ratio means the force generated is insufficient to rapidly decelerate the immense momentum of the hull, resulting in a very long stopping distance (often miles). **Why Options A, B, and C are Incorrect:** * **A) They have a bigger propeller:** While VLCCs *do* have large propellers (necessary to efficiently convert high torque into thrust at low RPM), the absolute size of the propeller is an engineering consequence of the required thrust, not the root cause of the slow response. Furthermore, a large, heavy propeller rotating slowly inherently contributes to the high inertia that makes the ship slow to respond, but the fundamental limiting factor is the engine power relative to the hull's mass (the P/W ratio). * **B) They have larger power to weight ratio:** This is factually incorrect and contradicts the operational characteristics described. If a VLCC had a *larger* power-to-weight ratio (like a container ship or a warship), it would be highly maneuverable, quick to accelerate, and have excellent stopping power. * **C) They possess smaller propellers:** This is factually incorrect. VLCCs require very large, highly optimized fixed-pitch propellers to generate the necessary high thrust efficiently at slow speeds. If they used smaller propellers, they would be highly inefficient and likely unable to reach their design speed.