What is a primary use of cross curves of stability?

The primary use of cross curves of stability is to construct a statical stability curve for specific conditions. Cross curves represent the relationship between the heel angle of a vessel and its righting arm, which directly informs how stable a vessel is at different angles of heel. These curves are valuable because they provide visual data that allows mariners to assess the stability at various loading conditions and configurations.

When a vessel heels, it experiences changes in the center of buoyancy and the position of the center of gravity. The cross curves illustrate how these changes affect the vessel's righting moment, enabling the determination of stability characteristics. By using these curves, one can accurately calculate the vessel's stability under various conditions, ensuring safety and compliance with stability criteria.

If examining why other choices do not pertain to the primary function of cross curves, consider that measuring fuel efficiency or calculating speed involves parameters unrelated to stability directly. Additionally, while draft measurement relates to a vessel's loading status, it does not provide the necessary data related to the righting moment or stability that cross curves are fundamentally designed to analyze. Therefore, the focus remains clearly on the role of cross curves in assessing stability through the construction of statical stability curves.