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Annex I · Positioning and technical details of lights and shapes

COLREGS Annex I · 3 — Horizontal positioning and spacing of lights

(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 m. The forward light shall be placed not more than one quarter of the length of the vessel from the stem.

(b) On a power-driven vessel of 20 m 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 all-round lights shall be placed at a horizontal distance of not less than 2 m from the fore and after centreline of the vessel in the athwartship direction.

(d) When only one masthead light is prescribed for a power driven vessel, this light shall be exhibited forward of amidships; except that a vessel of less than 20 m in length need not exhibit this light forward of amidships but shall exhibit it as far forward as is practicable.

(d) A power-driven vessel of less than 12 metres in length may carry the uppermost light at a height of less than 2.5 metres above the gunwale. When however a masthead light is carried in addition to sidelights and a sternlight or the all-round light prescribed in rule 23(d) (i) is carried in addition to sidelights, then such masthead light or all-round light shall be carried at least 1 metre higher than the sidelights.

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All COLREGS Rules and Annexes

Part A · General

Part B · Steering and sailing rules

Part C · Lights and shapes

Part D · Sound and light signals

Part E · Exemptions

Part F · Verification of compliance

Annex I · Positioning and technical details of lights and shapes

Annex II · Additional signals for fishing vessels fishing in close proximity

Annex III · Technical details of sound signal appliances

Annex IV

COLREGS oral exam questions and answers — all 114 examiner-style questions on one page, Rule by Rule, as a drill you mark yourself.

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An independent study aid built by CryoSim from the text of the 1972 Collision Regulations as amended. It is not an IMO publication and is not endorsed by the IMO — for navigation and legal purposes, use the official text.