Seaman's Handbook

ANNEX I. Positioning and technical details of lights and shapes

(a) When two masthead lights are prescribed for a power-driven vessel, the horizontal distance between them shall not be less than one-half of the length of the vessel but need not be more than 100 metres. The forward light shall be placed not more than one-quarter on the length of the vessel from the stem.(b) On a power-driven vessel on 20 metres or more in length the sidelights shall not be placed in front of the forward masthead lights. They shall be placed at or near the side of the vessel.(c) When the lights prescribed in Rule 27 (b) (i) or Rule 28 are placed vertically between the forward masthead light(s) and the after masthead light(s) these allround lights shall be placed at a horizontal distance of not less than 2 metres from the fore and aft centreline of the vessel in the athwartship direction.