Navigation Light (NL)
Navigation Light (NL) means the following lights:
.1 masthead light, sidelights, sternlight, towing light, all-round light, flashing light as defined in Rule 21 of COLREGs;
.2 all-round flashing yellow light required for air-cushion vessels by Rule 23 of COLREGs; and
.3 manoeuvring light required by Rule 34(b) of COLREGs.
The light source includes lamps, its housing, placing and means for delimiting the angle of lighting.
Source: IMO Resolution MSC.253(83), Recommendation on Performance Standards for Navigation Lights, Navigation Light Controllers and associated equipment, 8 October 2007, International Maritime Organization. Regulatory Guidance