COLREG - Vessel Identification by Lights
Identify vessel type and activity from observed navigation lights and shapes per COLREG Rules 23 to 31.
Vessel identification
Power-driven vessel >=50 m underway
Required action
Apply Rules 13-15 by encounter type
Formula, assumptions, and limits
COLREG Rules 23-31 establish navigation lights and shapes for various vessel types and activities. Lights are visible at night; shapes are equivalent day signals. The combination identifies vessel type, activity, and limitations on manoeuvrability.
Light combinations
| Pattern | Vessel/Activity | Rule |
|---|---|---|
| Masthead+sidelights+stern | Power-driven underway | Rule 23 |
| Sidelights+stern only | Sailing or rowing | Rule 25 |
| Two red over each other | Not Under Command | Rule 27 |
| Red-white-red | Restricted Ability to Manoeuvre | Rule 27 |
| Three red vertical | Constrained by draught | Rule 28 |
| Green over white | Trawling | Rule 26 |
| Red over white | Other fishing | Rule 26 |
| White over red | Pilot vessel | Rule 29 |
| All-round white | Anchor | Rule 30 |
| Three vertical red | Aground | Rule 30 |