All power driven vessels operating under periods of darkness or reduced visibility must display the following:
- Sidelights: The port sidelight displays a red light through a horizontal arc of 112.5 degrees. The starboard sidelight displays a green light through a horizontal arc of 112.5 degrees. Sidelights are mounted so that the light shows from straight ahead to 22.5 degrees abaft the beam on its respective side. On a vessel of less than 20 metres in length, the sidelights may be combined with one lantern installed on the bow of the vessel.
- All round white light: – A white light shining constantly over the horizon at an arc of 360 degrees.
If a vessel is more than 12 metres in length, it must display, from sunset to sunrise, a white masthead light forward and a stern light which together will display 360 degrees of white light.
If a power-driven vessel is less than 12 metres in length, it may, in addition to sidelights, exhibit an all-round white light instead of the masthead light and the sternlight (see image below).
REMEMBER: A port sidelight displays a red light on the port side (left when facing forward in the boat) and a starboard sidelight displays a green light on the starboard (right).