Basic navigation lights

According to the International Regulations of Preventing Collisions at Sea (ColReg), navigation lights have a specific
– color (white, red, green, yellow or blue),
– arc of illumination,
– range of visibility and
– location.
The basic navigation lights are:
– The masthead light is a white light, placed over the fore-and after-centerline of the vessel and that is visible over a 225°arc. From dead ahead to 22.5° abaft (behind) the beam on both sides of the vessel.
– The All-round light is a light, with the color determined by its use and is visible over a 360° arc.
– The sidelights are colored lights – red on port and green on the starboard side of the boat and is visible over a 112.5° arc, from dead ahead to 22.5° abaft the beam on each side.
– The stern light is a white light, centered on dead astern, and is visible over a 135° arc.
The side lights can be combined in one lantern at the bow. The sidelights can be combined with the stern light in a tricolour light at the masthead.
– The towing light, is a yellow light and is used in a towing operation. Centered on dead astern vertically above the stern light and is visible over a 135° arc.
– The flashing light is a yellow or blue flashing light with minimum 120 flashes per minute and is visible over a 360° arc.