Rule 22: Visibility of lights

The lights prescribed in these Rules shall have an intensity as specified in Section 8 of Annex I to these Regulations 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 stern light, 3 miles;
  a towing light, 3 miles;
  a white, red, green or yellow all-round light, 3 miles.
• In vessels of 12 metres or more in length but less than 50 metres in length:
  a masthead light, 5 miles; except that where the length of the vessel is less than 20 metres,3 miles;
  a sidelight, 2 miles;
  a sternlight, 2 miles;
  a towing light, 2 miles;
  a white, red, green or yellow all-round light, 2 miles.
• In vessels of less than 12 metres in length:
  a masthead light, 2 miles;
  a sidelight, 1 mile;
  a sternlight, 2 miles;
  a towing light, 2 miles;
  a white, red, green or yellow all-round light, 2 miles.
• In inconspicuous, partly submerged vessels or objects being towed:
  a white all-round light, 3 miles.