Navigation and Seamanship

4.1.6. Side lights

b.Side lights – means a green light on the star board side and a red light on the port side each showing an unbroken light over an arc of the horizon of 112.5 degrees and so fixed as to show the light from right ahead to 22.5 degrees abaft the beam on it respective side. In a vessel of less than 20 meters in length the side lights may be combined in one lantern carried on the fore and aft centerline of the vessel.