COLREG Rule 21 And Annex 1 Light And Shapes

Rule 21 Definitions of lights and shapes

(a) “Masthead light" means a white light placed over the fore and aft oenter line of the vessel showing an unbroken light over an arc oi the horizon of 225 degrees and so fixed as to show the light from right ahead to 22.5 degrees abai‘t the beam on either side of the vessel.

(b) ‘Sidelights" means a green light on the starboard 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 its respective side. In a vessel of less than 20 meters in length the sidelights may be combined in one lantern carried on the fore and at oentefline of the vessel.

(c) ‘Stern light" means a white light placed as nearly as practicable at the stern showing an unbroken light over an arc of the horizon of 135 degrees and so fixed as to show the light 67.5 degrees from right al't on each side of the vessel.

(d) ‘Towing light’ means a yellow light having the same characteristics as the ‘stemming" defined in paragraph (c) of this Rule.

(e) “All round light“ means a light showing an unbroken light over an arc of the horizon of 360 degrees.

(f) “Flashing light" means a light flashing at regular intervals at a frequency of 120 flashes or more per minute.



Extracts from Annex 1 - Positioning and technical details of lights and shapes

1. Definition

The term “height above the hull" means height above the uppermost continuous deck. This height shall be measured from the position vertically beneath the location of the light.

2. Vertical positioning and spacing of lights

(a) On a power’driven vessel of 20 meters or more in length the masthead lights shall be placed as followups:

(i) the forward masthead light, or if only one masthead light is carried, then that light, at a height above the hull of not less than 6 meters. and, if the breadth of the vessel exceeds 6 meters, then at a height above the hull not less than such breadth, so however that the light need not be placed at a greater height above the hull than 12 meters;

(ii) when two masthead lights are carried the alter one shall be at least 4.5 meters vertically higher than the forward one.

(b) The vertical separation of masthead lights of power-driven vessels shall be such that in all normal conditions of trim the after light will be seen over and separate from the forward light at a distance of 1,000 meters from the stem when viewed from sea level.

(g) The sidelights of a power-driven vessel shall be placed at a height above the hull not greater than three-quarters of that of the forward masthead light. They shall not be so low as to be interfered with by deck lights.



Extracts from Annex 1 - Positioning and technical details of lights and shapes (Continued)

6. Shapes

(a) Shapes shall be black and of the following sizes:

(l) a ball shall have a diameter of not less than 0.6 meter;

(ii) a cone shall have a base diameter of not less than 0.6 meter and a height equal to its diameter;

(iii) a cylinder shall have a diameter of at least 0.6 meter and a height of twice its diameter;

(iv) a diamond shape shall consist of two cones as defined in (ii) above having a common base;

(b) The vertical distance between shapes shall be at least 1.5 meters.