(a) On a power-driven vessel of 20 meters or more in length the masthead lights shall be placed as follows:
(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 5 meters, and, if the breadth of the vessel exceeds 5 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 8 meters.
(ii) When two masthead lights are carried the after one shall be at least 2 meters vertically higher than the forward one.
(b) The vertical separation of the 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 1000 meters from the stem when viewed from water level.
(c) The masthead light of a power-driven vessel of 12 meters but less than 20 meters in length shall be placed at a height above the gunwale of not less than 2.5 meters.
(d) The masthead light, or the all-round light described in Rule 23(d)(§ 83.23(d) of this chapter), of a power-driven vessel of less than 12 meters in length shall be carried at least one meter higher than the sidelights.
(e) One of the two or three masthead lights prescribed for a power-driven vessel when engaged in towing or pushing another vessel shall be placed in the same position as either the forward masthead light or the after masthead light, provided that the lowest after masthead light shall be at least 2 meters vertically higher than the highest forward masthead light.
(f)
(i) The masthead light or lights prescribed in Rule 23(a) (§ 83.23(a) of this chapter) shall be so placed as to be above and clear of all other lights and obstructions except as described in paragraph (f)(ii) of this section.
(ii) When it is impracticable to carry the all-round lights prescribed in Rule 27(b)(i)(§ 83.27(b)(i) of this chapter) below the masthead lights, they may be carried above the after masthead light(s) or vertically in between the forward masthead light(s) and after masthead light(s), provided that in the latter case the requirement of § 84.03(c) shall be complied with.
(g) The sidelights of a power-driven vessel shall be placed at least one meter lower than the forward masthead light. They shall not be so low as to be interfered with by deck lights.
(h) [Reserved]
(i) When the Rules in this subchapter E prescribe two or three lights to be carried in a vertical line, they shall be spaced as follows:
(i) On a vessel of 20 meters in length or more such lights shall be spaced not less than 1 meter apart, and the lowest of these lights shall, except where a towing light is required, be placed at a height of not less than 4 meters above the hull.
(ii) On a vessel of less than 20 meters in length such lights shall be spaced not less than 1 meter apart and the lowest of these lights shall, except where a towing light is required, be placed at a height of not less than 2 meters above the gunwale.
(iii) When three lights are carried they shall be equally spaced.
(j) The lower of the two all-round lights prescribed for a vessel when engaged in fishing shall be at a height above the sidelights not less than twice the distance between the two vertical lights.
(k) The forward anchor light prescribed in Rule 30(a)(i) (§ 83.30(a)(i)), when two are carried, shall not be less than 4.5 meters above the after one. On a vessel of 50 meters or more in length this forward anchor light shall be placed at a height or not less than 6 meters above the hull.
[79 FR 37921, July 2, 2014, as amended by USCG-2012-0102, 79 FR 68622, Nov. 18, 2014; USCG-2015-0433, 80 FR 44280, July 27, 2015]