At what height should a lantern be positioned for a sailing vessel under 20 meters?

The regulation for a sailing vessel under 20 meters specifies that any required sidelights and sternlight must be positioned at or near the top of the mast. This positioning is crucial because it allows for maximum visibility; placing the light higher ensures that it can be seen from a distance and from various angles, particularly in congested waters or during low-light conditions.

Having the lantern at the top of the mast also helps to delineate the vessel’s headings more clearly, with the side lights indicating the port and starboard sides of the vessel accurately. This visibility alignment is essential for other vessels to safely navigate around the sailing vessel and to avoid collisions.

Positioning the lantern elsewhere, such as at the bow or stern, would not provide the same level of visibility and could confuse other mariners regarding the vessel's orientation and direction of travel. Therefore, mounting the light at or near the top of the mast is both a safety measure and a compliance necessity according to maritime regulations.