(a) USWMS aids to navigation may have lateral or cardinal meaning.
(b) On a well defined channel including a river or other relatively narrow natural or improved waterway, an aid to navigation shall normally be a solid colored buoy. A buoy which marks the left side of the channel viewed looking upstream or toward the head of navigation shall be colored all black. A buoy which marks the right side of the channel viewed looking upstream or toward the head of navigation shall be colored all red. On a well defined channel, solid colored buoys shall be established in pairs, one on each side of the navigable channel which they mark, and opposite each other to inform the user that the channel lies between the buoys and that the user should pass between the buoys.
(c) On an irregularly defined channel, solid colored buoys may be used singly in staggered fashion on alternate sides of the channel provided they are spaced at sufficiently close intervals to inform the user that the channel lies between the buoys and that the user should pass between the buoys.
(d) Where there is no well-defined channel or when a body of water is obstructed by objects whose nature or location is such that the obstruction can be approached by a vessel from more than one direction, supplemental aids to navigation having cardinal meaning (i.e., pertaining to the cardinal points of the compass, north, east, south, and west) may be used. The use of an aid to navigation having cardinal meaning is discretionary provided that the use of such a marker is limited to wholly State owned waters and the State waters for private aids to navigation as defined and described in this part.
(e) Aids to navigation conforming to the cardinal system shall consist of three distinctly colored buoys.
(1) A white buoy with a red top may be used to indicate to a vessel operator that the operator must pass to the south or west of the buoy.
(2) A white buoy with a black top may be used to indicate to a vessel operator that the operator must pass to the north or east of the buoy.
(3) In addition, a buoy showing alternate vertical red and white stripes may be used to indicate to a vessel operator that an obstruction to navigation extends from the nearest shore to the buoy and that the operator must not pass between the buoy and shore. The number of white and red stripes is discretionary, provided that the white stripes are twice the width of the red stripes.
[CGFR 66-32, 31 FR 10321, July 30, 1966, as amended by CGD 97-018, 63 FR 33574, June 19, 1998; USCG-2001-10714, 69 FR 24982, May 5, 2004]