Section 13
Maritime Signalling Glossary
A reference guide to the terminology of coastal engineering and visual navigation.
- Automation
- The process of equipping lighthouses with automated lighting, monitoring, and fog signal systems, leading to the historical withdrawal of resident keepers.
- Beacon
- A stationary visual navigation mark, which may be lighted or unlighted, used to indicate a hazard, channel, or safe water.
- Bearing
- The horizontal direction of one terrestrial point from another, usually measured clockwise from a reference direction like True North.
- Buoy
- A floating object anchored to the seabed, used as an aid to navigation or to mark the location of a hazard or channel.
- Chart
- A nautical map displaying hydrographic data, depths, coastal features, and the location of navigation aids.
- Coastal navigation
- The practice of directing a vessel along a coastline using visual reference to landmasses, landmarks, and established aids to navigation.
- Daymark
- The unique, identifiable visual appearance of a navigation aid during daylight hours, often achieved through specific paint patterns or structural shapes.
- Fog signal
- An auditory warning device, such as a horn, siren, or historically a bell or explosive charge, used to warn mariners of hazards when visual signals are obscured by fog.
- Fresnel lens
- An optical device using concentric stepped glass prisms to capture and efficiently project light into a focused beam. Invented by Augustin-Jean Fresnel.
- Gallery
- The exterior walkway surrounding the lantern room at the top of a lighthouse tower, historically used for exterior cleaning and observation.
- Harbour
- A body of water sheltered from rough seas, often marked by specific breakwater lights or harbour entry beacons to guide vessels safely inward.
- Keeper
- The historically appointed individual responsible for operating the light, maintaining the station machinery, and ensuring the reliability of a lighthouse.
- Lantern room
- The glassed-in enclosure at the apex of a lighthouse tower that protects the lens and light source from the elements.
- Lantern
- Specifically refers to the glass enclosure, though sometimes colloquially used to mean the light source itself.
- Leading light
- A pair of beacons positioned at different elevations that, when aligned vertically in the navigator's view, indicate a safe navigational channel or line of approach.
- Light characteristic
- The specific sequence of flashes, eclipses, or colours that uniquely identifies a specific lighted navigation mark at night.
- Lighthouse
- A substantial enclosed tower structure constructed to elevate a primary navigation light to increase its geographical range.
- Lightship
- A specialised vessel moored over a hazard or in a critical position where building a permanent lighthouse structure was historically unfeasible.
- Navigation mark
- Any fixed or floating object placed specifically to assist mariners in determining their position or safe course.
- Optics
- In the context of lighthouses, the system of lenses, prisms, and reflectors used to manipulate and project the light source.
- Range
- The maximum distance at which a light can be seen, which can be defined by its geographical range (limited by earth's curvature) or luminous range (limited by intensity and weather).
- Sector light
- A navigation light that displays different colours (typically red, white, and green) across different horizontal arcs to indicate safe water or hazards.
- Signal
- Information conveyed intentionally, visually, acoustically, or electronically, to assist navigation.
- Tower
- The primary vertical architectural structure of a lighthouse, designed to elevate the light above the horizon and resist environmental forces.
- Trinity House
- The historical and current General Lighthouse Authority for England, Wales, the Channel Islands and Gibraltar.