Summary

A logical structure for the definition of terms describing some navigational aids has been developed. The main points are as follows:

• The navigational aids discussed are beacons, rather than GPS receivers, sextants, maps, charts or lists of lights.

• Those beacons that are navigational aids can be classified as built (implicitly assumed to be on land) and those that are floating (implicitly assumed to be moored in a fixed position).
• The next subdivision is between those that are lit and those that are unlit.
• Lighthouses fall into the ‘built and lit’ division, distinguished from lightstructures by the definition proposed above that includes a definition of the type of structure.
• Daymarks fall into the ‘built and unlit’ category
• Of the floating navigational aids, those that bear lights can be separated into Lightships, LANBYs, Lightfloats and lightbuoys.
• Unlit floating navigational aids are buoys or marks.

© 2003 Ken Trethewey