Part C · Lights and shapes · Rule 22
Visibility of Lights
22 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:
- “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”Each light must be bright enough to be seen at least as far as the range listed for the vessel’s length. Annex I section 8 sets the intensity needed, with the range measured in nautical miles. These are minimums for the light itself; in haze, rain or fog you may see it much later.
The bigger the vessel, the further her lights must reach. The ranges are minimums in clear conditions, not a promise of when you’ll see her.
22(a) In vessels of 50 metres or more in length:
– a masthead light, 6 miles;
– a sidelight, 3 miles;
– a sternlight, 3 miles;
– a towing light, 3 miles;
– a white, red, green or yellow all-round light, 3 miles.
- “In vessels of 50 metres or more in length”Length means length overall (Rule 3(j)).
- “a masthead light, 6 miles; a sidelight, 3 miles; a sternlight, 3 miles; a towing light, 3 miles; a white, red, green or yellow all-round light, 3 miles”The masthead light reaches 6 miles; everything else 3 miles. So at night you will usually see a large vessel’s masthead lights well before her sidelights tell you which way she is heading.
50 m and over: masthead 6 miles, all other lights 3 miles.
22(b) 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 12 metres or more in length but less than 50 metres in length”This covers vessels from 12 metres up to (but not including) 50 metres.
- “a masthead light, 5 miles; except that where the length of the vessel is less than 20 metres, 3 miles”The masthead light reaches 5 miles, or 3 miles on a vessel under 20 metres.
- “a sidelight, 2 miles; a sternlight, 2 miles; a towing light, 2 miles; a white, red, green or yellow all-round light, 2 miles”All the other lights reach 2 miles.
12 to 50 m: masthead 5 miles (3 miles under 20 m), all other lights 2 miles.
22(c) 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 vessels of less than 12 metres in length”Small craft under 12 metres.
- “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”Everything reaches 2 miles except the sidelights, which need only reach 1 mile. A small vessel’s red or green may only show when she is quite close.
Under 12 m: sidelights 1 mile, all other lights 2 miles.
22(d) In inconspicuous, partly submerged vessels or objects being towed:
– a white all-round light, 3 miles.
- “In inconspicuous, partly submerged vessels or objects being towed”Some tows sit very low in the water and are hard to see, for example a dracone (a towed flexible tank) or a partly submerged hulk. Rule 24(g) sets out their lights and shapes.
- “a white all-round light, 3 miles”Their all-round white lights must reach 3 miles, more than a small vessel’s lights, because the tow itself is so hard to spot.
Low, hard-to-see tows show all-round white lights visible at 3 miles.
