COLREG 1972 · rule 22 of 38
EnglishEN

Rule 22. Ranges at which the lights must be visible

By length of vessel:

Part of the convention Lights and shapes

By length of vessel:

  • 50 m or more: masthead 6 miles, sidelights, sternlight, towing light and all-round lights 3 miles.
  • 12 m up to 50 m: masthead 5 miles (3 miles if under 20 m), the rest 2 miles.
  • Under 12 m: masthead 2 miles, sidelights 1 mile, sternlight, towing light and all-round lights 2 miles.
  • Inconspicuous, partly submerged object under tow: all-round white 3 miles.
At sea it looks like this

A 10-metre yacht: her sidelights carry just one mile. At 20 knots of closing speed that mile is covered in three minutes, and the whole business of passing clear has to be settled inside those three minutes. That is exactly why small craft are told to be extra careful.

The rule says«The lights prescribed in these Rules shall have an intensity as specified in Section 8 of Annex I so as to be visible at the following minimum ranges: in vessels of 50 metres or more in length: a masthead light, 6 miles; a sidelight, 3 miles; a sternlight, 3 miles».

Check yourself

Light ranges for a vessel of 50 m or more?

Masthead 6 miles; sidelights, sternlight, towing light and all-round lights 3 miles.

Rule 22 (a).

Light ranges for a vessel from 12 to 50 m?

Masthead 5 miles (3 miles if under 20 m), the rest 2 miles.

Rule 22 (b).

Light ranges for a vessel under 12 m?

Masthead 2 miles, sidelights 1 mile, sternlight, towing light and all-round lights 2 miles.

Rule 22 (c).

Part of the convention: Lights and shapes