Factors Associated with Navigational Lights
There are only three light colors in common use on fixed lighted
navigation aids--white, green, and red. All lighted navigation aids,
regardless of the color of their light, are symbolized on a chart either by
a magenta colored ray in the form of an exclamation point or by a one-
eighth-inch magenta circle, superimposed over a black dot indicating the
location of the light.
On charts, the color of the light, if other than white, is indicated by the
abbreviations R for red and G for green, written near the light symbol.
A white light has no abbreviation on a chart. Thus, if a magenta light
symbol appears on a chart with no color abbreviation nearby, the
navigator should assume its color to be white.
In the Light List and List of Lights, however, the color of a white light is
indicated by the abbreviation W.
If a light is made to change color in a regular pattern, either by
alternately energizing different color lights or by passing colored lenses
around the same light, the light is an alternating light, abbreviated Al.
Alternating lights used in conjunction with different phase characteristics
show a very distinctive appearance that cannot be easily mistaken. Their
use is generally reserved for special applications requiring the exercise
of great caution, such as airport beacons, harbor entrance lights, and