What is the diameter of a black cone used on vessels?

The correct diameter of a black cone used on vessels is 0.6 meters. According to the COLREGs regulations, the dimensions of shapes that vessels are required to display while at anchor or in a specific status are clearly defined to ensure visibility and recognition. The use of a black conical shape indicates that a vessel is constrained by its draft, and this specific measurement is standardized for consistency across international waters. Ensuring this specific diameter aids in maintaining the safety and communication standards vital for maritime navigation.