Final answer:
The question's premise about tankers with high centers of gravity is incorrect; a low center of gravity is preferred for stability. A loaded oil tanker sits lower in water due to the weight of the oil it carries, which increases the vessel's overall weight and displacement in comparison to an empty one.
Step-by-step explanation:
The question mistakenly asserts that a tanker with a high center of gravity is preferred over one with a low center of gravity, which may not be the case, especially regarding stability concerns. In physics, the center of gravity is the point where the total weight of the body is assumed to be concentrated. A high center of gravity in a vehicle, like a tanker, can lead to instability because it makes the vehicle easier to tip over. On the other hand, a low center of gravity contributes to a more stable equilibrium, making it harder for the vehicle to tip over as shown in Figure 12.3, where the distribution of mass affects the position of the center of mass (CM).
Regarding the density of oil versus water, the density of oil is less than that of water; however, a loaded oil tanker sits lower in water due to the weight of the oil it carries. Adding mass to the tanker increases its overall weight, causing it to displace a larger volume of water, and thus, it sits lower in the water. This concept is explained by Archimedes' principle, which states that the upward buoyant force exerted on a body immersed in a fluid is equal to the weight of the fluid that the body displaces.