Application (lights & shapes)
In plain language
Lights are exhibited from sunset to sunrise in all weathers, and in restricted visibility by day as well; shapes are exhibited by day. The rules on lights are complied with in all weathers.
Full text of Rule 20
Rules in this Part shall be complied with in all weathers.
The Rules concerning lights shall be complied with from sunset to sunrise, and during such times no other lights shall be exhibited, except such lights as cannot be mistaken for the lights specified in these Rules or do not impair their visibility or distinctive character, or interfere with the keeping of a proper look-out.
The lights prescribed by these Rules shall, if carried, also be exhibited from sunrise to sunset in restricted visibility and may be exhibited in all other circumstances when it is deemed necessary.
The Rules concerning shapes shall be complied with by day.
The lights and shapes specified in these Rules shall comply with the provisions of Annex I to these Regulations.
Reproduced from the COLREGs 1972 (as amended) for study. Always verify against the official IMO publication.
Key points
- 1
Lights from sunset to sunrise — and in restricted visibility by day.
- 2
No other lights may be shown that could be mistaken for the prescribed lights.
- 3
Shapes are exhibited by day.