Navigational aid

Common types of such aids include lighthouses, buoys, fog signals, and day beacons.

The standards are defined by the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA).

If the mark is a pillar or spar shape, then a topmark is fitted which is either cylindrical or conical as appropriate.

Region B is the Americas (excluding Greenland) along with Japan, Korea and the Philippines.

[1] In IALA region A where a minor channel branches off to port the mark at the junction would be a red cylinder with a green band.

[4] Cardinal marks warn of a danger (wrecks, shoals, bends, spits etc.)

[6] Indicates a newly discovered or created danger that is not yet marked on charts (or in update notices thereto).

[8] A sector light is one which shows different colours depending upon the angle of approach.

On non-lateral markers, there are some shapes that show certain things: AtoNs can be integrated with automatic identification system (AIS).

AIS transmitted form an actual aid (buoy, lighthouse etc.)

[12] Each AIS AtoN must have a unique Maritime Mobile Service Identity (MMSI) number.

[13] Lead marks (as in "leading a ship into a safe place") and lights are fixed markers that are laterally displaced to allow a mariner to navigate a fixed channel along the preferred route.

The entrance to the inner harbour of the Port of Fremantle , Australia, with a yellow special mark at left, a region A red port lateral mark at right, and a region A green starboard lighthouse in the background
Region B green port lateral marks (with Galápagos sea lions (Zalophus wollebaeki)) in the Galápagos Islands
Diagram showing lateral, non-lateral, and special purpose markers as seen on an IALA Region B nautical chart .
Triangle shaped lead marks with lights.
large buoy in storage, Homer, Alaska