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Part C · Lights and shapes

COLREGS Rule 23 — Power-driven Vessels underway

(a) A power-driven vessel underway shall exhibit:

(i) a masthead light forward;

(ii) a second masthead light abaft of and higher than the forward one; except that a vessel of less than 50 meters in length shall not be obliged to exhibit such light but may do so;

(iii) sidelights;

(iv) a sternlight.

(b) An air-cushion vessel when operating in the non-displacement mode shall, in addition to the lights prescribed in paragraph (a) of this Rule exhibit an all-round flashing yellow light.

(c) A WIG craft only when taking off, landing and in flight near the surface shall, in addition to the lights prescribed in paragraph (a) of this Rule, exhibit a high intensity all-round flashing red light.

(d)

(i) A power-driven vessel of less than 12 meters in length may in lieu of the lights prescribed in paragraph (a) of this Rule exhibit an all-round white light and sidelights:

(ii) a power-driven vessel of less than 7 meters in length whose maximum speed does not exceed 7 knots may in lieu of the lights prescribed in paragraph (a) of this Rule exhibit an all-round white light and shall, if practicable, also exhibit sidelights;

(iii) the masthead light or all-round white light on a power-driven vessel of less than 12 meters in length may be displaced from the fore and aft centreline of the vessel if centreline fitting is not practicable, provided that the sidelights are combined in one lantern which shall be carried on the fore and aft centreline of the vessel or located as nearly as practicable in the same fore and aft line as the masthead light or the all-round white light.

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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.