COLREG - Navigation Light Visibility Range
Required minimum visibility range for navigation lights by vessel length per COLREG Annex I.
Minimum visibility range
6.0nm
Light category
Class A - large vessel
Formula, assumptions, and limits
COLREG Annex I Section 2 specifies minimum visibility ranges for navigation lights. The range depends on vessel length (longer vessels need brighter lights for greater detection range) and light type (masthead lights need longer range than sidelights for forward identification).
Visibility ranges (nm)
| Vessel length | Masthead | Sidelight | Sternlight | All-round |
|---|---|---|---|---|
| >=50 m | 6 | 3 | 3 | 3 |
| 12-50 m | 5 (3 if <20m) | 2 | 2 | 2 |
| <12 m | 2 | 1 | 2 | 2 |