What are cross curves of stability used for?

Cross curves of stability serve a crucial role in marine stability assessments by illustrating the relationship between the angle of heel and the righting arm under various loading conditions. These curves provide valuable information about how a vessel will behave when it tilts or heels due to external forces, such as wind or waves.

The righting arm is the horizontal distance from the center of gravity to the center of buoyancy when the vessel is heeled over; a larger righting arm indicates greater stability, as it provides a stronger force to return the vessel to an upright position. By analyzing the cross curves, vessel operators and designers can determine how different loading conditions affect stability, enabling them to make informed decisions regarding cargo distribution, vessel design, and safety measures.

In contrast, the other choices address different aspects of vessel operation or design that are not related to the purpose of cross curves of stability. For instance, while measuring fuel efficiency, determining load capacity, and the relationship between speed and wave height are significant for vessel operations and safety, they do not pertain to the primary use and analysis provided by cross curves of stability.