What is the significance of the center of gravity (G) in ship stability?

The center of gravity (G) is a critical concept in ship stability as it represents the point at which the overall weight of the vessel is concentrated and balanced. Understanding G is essential for analyzing how a ship behaves when it is subjected to external forces, such as waves and wind.

When a vessel is floating, the location of the center of gravity influences the ship’s stability. If the center of gravity is too high, the vessel may be prone to capsizing, because a higher center of gravity results in a smaller metacentric height (the distance between the center of gravity and the metacenter). Conversely, a lower center of gravity contributes to greater stability; a well-designed vessel will strive to keep this point low to improve its stability and reduce the risk of tipping over.

To further illustrate this point, the stability of a ship is assessed using its center of gravity in conjunction with its center of buoyancy (the point where the volume of water displaced by the hull is centered). The relationship between these centers determines the vessel's ability to right itself after heeling. Thus, the center of gravity directly relates to how well a ship maintains its upright position under various conditions.