Which factor primarily affects the center of gravity of a vessel?

The center of gravity of a vessel is primarily influenced by the distribution and weight of cargo and equipment onboard. As the load on a vessel changes, whether through loading or unloading cargo, the center of gravity shifts accordingly. When cargo is placed in different locations within the ship, it can raise or lower the overall center of gravity, which directly impacts the vessel's stability.

This is crucial for maintaining balance and preventing capsizing. For example, if heavy equipment is positioned high in the cargo hold, it can elevate the center of gravity, leading to increased susceptibility to heeling or rolling in rough waters. Conversely, moving weight lower in the vessel can enhance stability by lowering the center of gravity.

Other factors mentioned, such as the weight of the hull construction or the type of engine installed, do contribute to the overall stability but do not have the same immediate and variable impact on the center of gravity as the distribution and weight of the cargo and equipment. While the design of the vessel's sails may influence factors like drive and balance, it does not directly affect the center of gravity in the context of stability assessment.