When is a vessel allowed to show an all-round light instead of a masthead and stern light?

A vessel is allowed to show an all-round light instead of separate masthead and stern lights when it is under 12 meters in length. This regulation is part of the International Regulations for Preventing Collisions at Sea (COLREGs), which simplifies the lighting requirements for smaller vessels, recognizing that vessels of this size often operate in less congested waters and may not need the full suite of lights required for larger vessels.

For vessels under 12 meters, an all-round white light is acceptable because it provides adequate visibility without the complexity of multiple lights. This arrangement helps ensure that small vessels can maintain their safety while navigating and avoids the potential for confusion that might arise from needing to manage multiple lights.

The other options refer to lengths that do not align with this regulation, as vessels over 12 meters are required to display separate masthead and stern lights to enhance their visibility and identify their position and direction of travel to other vessels.