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COLREG - Navigation Light Visibility Range

Required minimum visibility range for navigation lights by vessel length per COLREG Annex I.

COLREGAnnex INavigation lightsVisibility
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Formula, assumptions, 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 lengthMastheadSidelightSternlightAll-round

=50 m6333 12-50 m5 (3 if 222 2122

In short

Required minimum visibility range for navigation lights by vessel length.

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