U.S. Code > Title 33 Navigation and Navigable Waters > CHAPTER 34—INLAND NAVIGATIONAL RULES (§§ 2001—2073) > SUBCHAPTER I—RULES (§§ 2001—2038) > Part C—Lights and Shapes (§§ 2020—2031) > § 2027. Vessels not under command or restricted in their ability to maneuver (Rule 27)

§ 2027. Vessels not under command or restricted in their ability to maneuver (Rule 27)

(a) Vessels not under command
A vessel not under command shall exhibit:
(i) two all-round red lights in a vertical line where they can best be seen;
(ii) two balls or similar shapes in a vertical line where they can best be seen; and
(iii) when making way through the water, in addition to the lights prescribed in this paragraph, sidelights and a sternlight.
(b) Vessels restricted in their ability to maneuver
A vessel restricted in her ability to maneuver, except a vessel engaged in mineclearance operations, shall exhibit:
(i) three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle light shall be white;
(ii) three shapes in a vertical line where they can best be seen. The highest and lowest of these shapes shall be balls and the middle one a diamond;
(iii) when making way through the water, masthead lights, sidelights and a sternlight, in addition to the lights prescribed in subparagraph (b)(i); and
(iv) when at anchor, in addition to the lights or shapes prescribed in subparagraphs (b)(i) and (ii), the light, lights or shapes prescribed in Rule 30.
(c) Vessels engaged in towing operations
A vessel engaged in a towing operation which severely restricts the towing vessel and her tow in their ability to deviate from their course shall, in addition to the lights or shapes prescribed in subparagraphs (b)(i) and (ii) of this Rule, exhibit the lights or shape prescribed in Rule 24.
(d) Vessels engaged in dredging or underwater operations
A vessel engaged in dredging or underwater operations, when restricted in her ability to maneuver, shall exhibit the lights and shapes prescribed in subparagraphs (b)(i), (ii), and (iii) of this Rule and shall in addition, when an obstruction exists, exhibit:
(i) two all-round red lights or two balls in a vertical line to indicate the side on which the obstruction exists;
(ii) two all-round green lights or two diamonds in a vertical line to indicate the side on which another vessel may pass; and
(iii) when at anchor, the lights or shape prescribed by this paragraph, instead of the lights or shapes prescribed in Rule 30 for anchored vessels.
(e) Vessels engaged in diving operations
Whenever the size of a vessel engaged in diving operations makes it impracticable to exhibit all lights and shapes prescribed in paragraph (d) of this Rule, the following shall instead be exhibited:
(i) Three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle light shall be white.
(ii) A rigid replica of the international Code flag “A” not less than 1 meter in height. Measures shall be taken to insure its all-round visibility.
(f) Vessels engaged in mineclearance operations
A vessel engaged in mineclearance operations shall, in addition to the lights prescribed for a power-driven vessel in Rule 23 or to the lights or shape prescribed for a vessel at anchor in Rule 30, as appropriate, exhibit three all-round green lights or three balls. One of these lights or shapes shall be exhibited near the foremast head and one at each end of the fore yard. These lights or shapes indicate that it is dangerous for another vessel to approach within 1,000 meters of the mineclearance vessel.
(g) Vessels of less than 12 meters in length
A vessel of less than 12 meters in length, except when engaged in diving operations, is not required to exhibit the lights or shapes prescribed in this Rule.
(h) Signals of vessels in distress and requiring assistance
The signals prescribed in this Rule are not signals of vessels in distress and requiring assistance. Such signals are contained in Annex IV to these Rules.