Navigation Aid


Definition of Navigation Aid

Navigation aids are man-made objects used to determine the boat’s position and to chart a safe course on waterways. They can be visible, audible, or electronic and include fog signals, day beacons, buoys, lights, lightships, and marks.

Used together with nautical charts, they provide valuable information about water depths, isolated dangers, and safe landfall areas.

For night travel, boat operators may periodically use a forward-facing flood light, such as the Maxillume H60 Bracket Mount Flood Light, to spot navigation aids in a water channel.

There are two main types of navigation aids:

  • Beacons: Are fixed permanently to land or the sea floor and can be equipped with lateral or non-lateral aids to show the navigable channel or information and rules, respectively.
  • Buoys: Are floating devices anchored to the sea floor, whose distinct colors indicate how to navigate around them. They’re less accurate than beacons.

Navigation aids conform to the common standard set by the International Association of Lighthouse Authorities (IALA).

Here are a few basic principles from the IALA standard that apply across navigable waters:

  • Port-side aids: Odd-numbered, green, and on the left side as you head upstream
  • Starboard-side aids: Even-numbered, red, and situated on the right side as you head upstream
  • Number system: The numbers on buoys and beacons ascend as you travel upstream or from sea to harbor
  • Intracoastal Waterway marks: When navigating clockwise around the U.S. coast, red is on the right or shore side, and the numbers ascend. They’re also identified by a yellow reflector at the bottom.

illustrations of various navigation aids

Below is a diagram showing how navigation aids appear to a mariner navigating a waterway during the day.

daytime view of watercourse navigated by sight

The same waterway looks different by night, as shown below.

nighttime view of watercourse navigated by sight

Lastly, the boat operator looking at the same waterway on a chart would see the image below.

watercourse navigation represented in a nautical chart

Example of Navigation Aid in a Sentence

"The islands are exposed to high winds and fast tides, necessitating numerous lighthouses as navigation aids."

Synonyms: NAVAID, aid to navigation, ATON

Related Terms for Navigation Aid