When two masthead lights are carried on a vessel, what are the requirements for vertical positioning/separation and visibility?

The correct response highlights that when two masthead lights are carried on a vessel, they must be separated by a specific vertical distance. This requirement ensures that the lights are distinguishable from one another, aiding in the identification of the type of vessel and its intentions by others in the vicinity. Proper vertical separation is essential for maintaining safety and clarity in navigation, as it prevents confusion that could arise if the lights appeared co-located.

The specific vertical distance between the lights is determined by the regulations laid out in the COLREGs. Adhering to this regulation allows other vessels to interpret the signals correctly, especially in situations where visibility might be limited or when vessels are navigating in close proximity.

Vertical positioning and separation of masthead lights enhance their visibility and efficacy, ensuring they serve their purpose of indicating the vessel's presence and heading. The answer reflects the importance of observing these navigational standards as part of good seamanship and compliance with international maritime rules.