Part C · Lights and shapes · Rule 20
Application
20(a) Rules in this Part shall be complied with in all weathers.
- “Rules in this Part shall be complied with in all weathers”Part C is Rules 20 to 31: the lights and shapes every vessel must show. Bad weather is no excuse for not showing them; in poor visibility they matter most.
Show the correct lights and shapes in every weather.
20(b) The Rules concerning lights shall be complied with from sunset to sunrise and during such times no other lights shall be exhibited, except such lights as cannot be mistaken for the lights specified in these Rules or do not impair their visibility or distinctive character, or interfere with the keeping of a proper look-out.
- “The Rules concerning lights shall be complied with from sunset to sunrise”Navigation lights are shown from sunset to sunrise, whatever the visibility. They tell other vessels what you are, which way you are heading and what you are doing.
- “and during such times no other lights shall be exhibited, except such lights as cannot be mistaken for the lights specified in these Rules or do not impair their visibility or distinctive character, or interfere with the keeping of a proper look-out”Other lights, such as deck working lights or accommodation lights, are only allowed if they can’t be mistaken for navigation lights, don’t make your navigation lights harder to see or recognise, and don’t spoil the look-out (Rule 5), for example by ruining night vision.
Navigation lights from sunset to sunrise. Any other light must not confuse, hide your navigation lights or spoil the look-out.
20(c) The lights prescribed by these Rules shall, if carried, also be exhibited from sunrise to sunset in restricted visibility and may be exhibited in all other circumstances when it is deemed necessary.
- “The lights prescribed by these Rules shall, if carried, also be exhibited from sunrise to sunset in restricted visibility”By day in restricted visibility (fog, mist, falling snow, heavy rain and so on, Rule 3(l)), switch your navigation lights on as well. “If carried” means a vessel shows the lights she has; it doesn’t require her to fit extra ones for daytime use.
- “and may be exhibited in all other circumstances when it is deemed necessary”You may also show them by day at any other time you judge it helps, for example in poor light at dawn or dusk.
Lights on in restricted visibility, day or night. You may also use them by day whenever you think it helps.
20(d) The Rules concerning shapes shall be complied with by day.
- “The Rules concerning shapes shall be complied with by day”Day shapes (balls, cones, cylinders and diamonds) are shown by day. Rules 24 to 28 and 30 say which shapes a vessel shows; for example a vessel at anchor shows one ball (Rule 30). In restricted visibility by day, a vessel shows both her shapes and her lights (20(c)).
Shapes by day, lights by night, and both by day in restricted visibility.
20(e) The lights and shapes specified in these Rules shall comply with the provisions of Annex I to these Regulations.
- “The lights and shapes specified in these Rules shall comply with the provisions of Annex I to these Regulations”Annex I gives the technical detail: the positioning and spacing of lights, sidelight screens, the size of shapes, light colours and intensity, and the horizontal and vertical sectors. The minimum ranges at which lights must be visible are in Rule 22.
The Rules say which lights and shapes to show; Annex I says exactly how they must be made and fitted.