What size is the shape used to indicate a diamond signal on a vessel?

The diamond signal, which is an important day signal used to convey specific messages under the International Regulations for Preventing Collisions at Sea (COLREGs), must be at least 0.6 meters in size. This specification ensures that the signal is adequately visible from a distance, thereby effectively communicating the vessel's status or intentions to other mariners. The visibility of the signal is crucial for maintaining safe navigation and preventing potential collisions.

Although the proportionality to the vessel's size is a consideration in some contexts, the minimum size requirement is specifically mandated to ensure that the signal can be reliably seen and interpreted by other vessels. The 0.6 meters standard has been established as a balance between visibility and practicality, solidifying its role as a recognizable warning or indication at sea.