daymarks

Daymarks are fixed navigational markers used by mariners to identify locations, channels, hazards, or lines of position during daylight. They serve as the daylight counterpart to lighted aids to navigation, offering a conspicuous target that can be seen from a distance without the need for illumination. Daymarks are part of a country’s aids to navigation system and are designed to be distinct and recognizable in various weather and light conditions.

Daymarks come in a variety of forms and appearances. They may be architectural structures, towers, poles, or painted markers mounted on land or on the water’s edge. Common characteristics include high contrast colors and simple geometric shapes so they stand out against the surrounding environment. The exact color patterns, shapes, and identifiers are typically defined by national authorities and by the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA), and may vary by region.

Two common daymark concepts are leading marks and range markers. Leading marks are a paired set of daymarks placed on shore or a jetty; when viewed from the sea, the marks align to indicate the correct line for a channel or approach. Range markers use similar principles to guide vessels along safe routes by providing a visual alignment cue during daylight.

Maintenance and updating of daymarks are the responsibility of national hydrographic and maritime authorities. They are inspected for legibility, access, and replacement of faded colors or damaged structures to ensure reliable daytime navigation.