1The rule in plain words
In one sentence…
At night: green over white for trawling; red over white for other fishing; when making way, add sidelights and a sternlight.
How do you recognise trawling?
It shows two all-round lights: green above and white below. It also has a masthead light abaft of and higher than the green light; a vessel less than 50 metres long is not obliged to show it, but may do so.
What about fishing other than trawling?
It shows two all-round lights: red above and white below. If outlying gear extends more than 150 metres horizontally from the vessel, add an all-round white light or a cone apex upwards in the direction of the gear.
What does «making way» change?
When the vessel is moving through the water, add sidelights and a sternlight to the fishing lights prescribed in the relevant paragraph.
What shape is shown by day?
Instead of the corresponding lights, show two cones with their apexes together, one above the other. For outlying gear, the cone has its apex upwards and points in the gear's direction.
2See it in 3D
Turn the vessel or pick bow, stern, port or starboard: this is how her lights look at night.
An interactive 3D illustration is shown here. The same content is described in the rule text and key takeaways below.
3Key points
- 1.
Trawling = green above · white below.
- 2.
Other fishing = red above · white below.
- 3.
More than 150 m of gear → white light or cone towards it.
- 4.
Making way → sidelights + sternlight; not fishing → length-based lights.
4Frequent mistakes
Wrong: "Green over white works for every fishing vessel."
Right: Green over white identifies trawling; other fishing uses red over white.
Wrong: "Exactly 150 metres already triggers the gear light."
Right: The gear must extend more than 150 metres horizontally from the vessel.
Wrong: "After stopping fishing, I keep this Rule's lights."
Right: When not fishing, show only the lights and shapes prescribed for a vessel of her length.
5Exam keys & interpretation
Exam keys
"More than 150 m" means over 150 m: exactly 150 m does not meet the threshold.
"Less than 50 m" removes the masthead-light obligation; the vessel may still show it.
Green over white = trawling; red over white = other fishing: that distinction decides many answers.
How to read it
Classify trawling or other fishing first; then check gear, making way and length in the order asked.
Cone shapes are the daytime alternative to lights; outlying gear fixes the cone's direction.
6Official text
IMO COLREG 1972U.S. Coast Guard — International Navigation Rules (2024)
Full wording of the rule, reproduced from the official source below.
(a) A vessel engaged in fishing, whether underway or at anchor, shall exhibit only the lights and shapes prescribed in this Rule.
(b) A vessel when engaged in trawling, by which is meant the dragging through the water of a dredge net or other apparatus used as a fishing appliance, shall exhibit:
(i) two all-round lights in a vertical line, the upper being green and the lower white, or a shape consisting of two cones with their apexes together in a vertical line one above the other;
(ii) a masthead light abaft of and higher than the all-round green light; a vessel of less than 50 meters in length shall not be obliged to exhibit such a light but may do so;
(iii) when making way through the water, in addition to the lights prescribed in this paragraph, sidelights and a sternlight.
(c) A vessel engaged in fishing, other than trawling, shall exhibit:
(i) two all-round lights in a vertical line, the upper being red and the lower white, or a shape consisting of two cones with apexes together in a vertical line one above the other;
(ii) when there is outlying gear extending more than 150 meters horizontally from the vessel, an all-round white light or a cone apex upwards in the direction of the gear;
(iii) when making way through the water, in addition to the lights prescribed in this paragraph, sidelights and a sternlight.
(d) The additional signals described in Annex II to these Rules apply to a vessel engaged in fishing in close proximity to other vessels engaged in fishing.
(e) A vessel when not engaged in fishing shall not exhibit the lights or shapes prescribed in this Rule, but only those prescribed for a vessel of her length.7Test your knowledge
Which lights identify a vessel engaged in trawling?
Keep studying…
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