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Daymark

Daytime aid to navigation

Wikipedia contributorsAdapted for Fathomly · View authors
1 min read
Source updated June 1, 2026
Image credit is listed at the end of this article.

A daymark is a navigational aid for sailors and pilots, distinctively marked to maximize its visibility in daylight.

The word is also used in a more specific, technical sense to refer to a signboard or daytime identifier that is attached to a day beacon or other aid to navigation. In that sense, a daymark conveys to the mariner during daylight hours the same significance as the aid's light or reflector does at night. Standard signboard shapes are square, triangular, and rectangular, and standard colours are red, green, orange, yellow, and black.

01Notable daymarks

Triangular daymark in the marina of Ystad, 2021
Triangular daymark in the marina of Ystad, 2021

02Symbols used on US charts

Chart symbols used by the US National Oceanic and Atmospheric Administration Department, 2013.

Paper chart Simplified Simplified symbol name
Square or rectangular daymark
Triangular daymark, point up
Triangular daymark, point down
Retro reflector
Scharhörn daymark in 1898
Scharhörn daymark in 1898
Watch videos about DaymarkExplainers and documentaries on YouTube (opens in a new tab)

Sources and credits

This article is adapted from the Wikipedia article “Daymark”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.

Images, from Wikimedia Commons:

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Related topics

Landmark

A landmark is a recognizable natural or artificial feature used for navigation, a feature that stands out from its near environment and is often visible from long distances. In modern-day use, the term can also be applied to smaller structures or features that have become local or national symbols.

Lighthouse

A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lenses and to serve as a beacon for navigational aid for maritime pilots at sea or on inland waterways. Lighthouses mark dangerous coastlines, hazardous shoals, reefs, rocks, and safe entries to harbors; they also assist in aerial navigation.

Sea mark

A sea mark, also seamark and navigation mark, is a form of aid to navigation and pilotage that identifies the approximate position of a maritime channel, hazard, or administrative area to allow boats, ships, and seaplanes to navigate safely. There are three types of sea mark: beacons fixed to the seabed or on shore, towers built on the shore or on a submerged rock/object (especially in calmer waters), and buoys (consisting of a floating object that is usually anchored to a specific location on the bottom of the sea or to a submerged object).