Cross curves of stability are calculated for which conditions?

Cross curves of stability are calculated under static conditions. This is because cross curves provide a visual representation of a vessel's stability at different angles of heel, essentially illustrating how the center of buoyancy shifts as the vessel tilts. These curves are derived from the hydrodynamic principles that apply when the vessel is at rest or in a steady state, meaning that the forces acting on the vessel are balanced and there is no acceleration making the stability characteristics purely structural.

Static stability focuses on the precise positioning of the center of gravity and center of buoyancy, and how they interact when the vessel is inclined. The cross curves allow for an assessment of stability at various heel angles without the influence of dynamic forces such as wind or waves, which are more relevant in dynamic conditions or when the vessel is in action. Therefore, the calculations for cross curves are crucially based on the static stability characteristics of the vessel, making it an essential consideration for vessel design and operational safety.