On a vessel of 20 meters or more, what is the spacing between black balls?

The correct answer indicates that when displaying black balls on a vessel of 20 meters or more in length, the spacing between these balls must be 1.5 meters. This requirement is specified in the COLREGs, which sets forth guidelines for the display of shapes and lights by vessels to ensure clear and effective communication of their status and activities, particularly in terms of their ability to maneuver or their operational state.

The spacing is crucial for visibility and allows other vessels to readily assess the size, intentions, and maneuverability of the vessel displaying these shapes. A distance of 1.5 meters between the balls is specifically defined to help maintain a standard that promotes safety and aids in navigation during situations such as restricted visibility or conditions where sightlines may be compromised.

This regulation ensures that the shapes are easily identifiable and clearly signal to other mariners the nature of the vessel in question. In contrast, other spacing choices would not adhere to the established conventions, potentially leading to confusion or misinterpretation regarding the vessel's status.