Navigation and Seamanship

4.3.9. Flashing

Flashing: L ights are described as flashing – when the time on is less than they are off. A single flash showing at regular intervals, the duration of light always being less than the duration of darkness. When a light is flashing at the rate of not more than 30 per minute the light is called flashing light.

Quick Flashing : When a light flashing at the rate of not less than 60 flashes per minute, then the light is called Quick flashing light.

Interrupted Quick Flashing : This is the characteristics of a light with groups of six quick flashes repeated at intervals of ten seconds.

Occulting: A light totally eclipsed at regular intervals, the duration of light always being greater than the duration of darkness. Lights are termed as occulting, when they are on more than they are off (eclipsed).

If the times on and off are equal the light is designated as equal interval or isophase.

Group Flashing: Groups of two or more flashes showing at regular intervals.

Group Occulting: A light with a group of two or more eclipses at regular intervals.

Equal Interval (Isophase): A single flash with the duration of light equal to that of darkness.

Morse code: Light in which flashes of different durations are grouped to produce a Morse character or characters.

Alternating: Rhythmic lights which exhibit different colors during each sequence.