DayMark

A daymark is a fixed navigational aid designed to be visible in daylight. It serves to indicate the presence of a navigable channel, a coastal feature, or a hazard, helping mariners determine their position and correct course without relying on lights. Daymarks complement nocturnal aids such as lighthouses and lighted buoys and are typically non-illuminated.

Appearance and construction: Daymarks come in a variety of shapes and patterns chosen for quick recognition in daylight. Common forms include cones, cylinders, spheres, pyramids, or posts. They are usually painted in high-contrast colors and may bear bands, stripes, or numerals to convey identity or chart reference. Many are fixed to shores, rocks, piers, or offshore structures and may be integrated into national or regional buoyage systems that define their meaning and location.

Functions: Daymarks mark channels, shoals, submerged dangers, or coastal features. Mariners use their shape, color, and position on charts to determine whether they are on the correct course and to fix their bearings. In many systems, daymarks are used in conjunction with corresponding night aids to provide continuous guidance across day and night.

History and context: The use of fixed daylight markers evolved alongside other navigational aids, with standardization occurring in the 19th and 20th centuries as maritime authorities sought consistent marking schemes. Today, daymarks remain an important, non-powered means of navigation, especially in areas where electronic systems may be unreliable or unavailable.

Other uses: The term daymark can also refer to daylight-visible landmarks used in land navigation or orienteering to help map readers orient themselves.