What is the height requirement for sidelights on a power-driven vessel?

The height requirement for sidelights on a power-driven vessel being not greater than three-quarters of the height of the forward masthead light aligns with the regulations set forth under the COLREGs. This standard is in place to ensure that sidelights are positioned correctly relative to the other lights on a vessel, particularly for optimal visibility and safe navigation.

In practice, having sidelights at this specified height maintains proper alignment with the forward masthead light, allowing other vessels to clearly understand the orientation and direction of the power-driven vessel from various angles, especially at night or in reduced visibility conditions. This visual clarity is crucial for preventing collisions, as it helps identify the nature of the other vessel’s activities, particularly whether it is underway or at anchor, and its course.

This height restriction also serves to ensure that the sidelights remain visible to oncoming vessels while not infringing on the visibility of the masthead light, which is critical for determining the type of vessel and safety distances.