(1) Lateral marks define the port and starboard sides of a route to be followed. They may be either beacons or buoys.

(2) Side marks are lateral marks which advise the mariner to stay to one side of the mark. Their most frequent use is to mark the sides of channels; however, they may be used individually to mark obstructions outside of clearly defined channels. Side marks are not always placed directly on a channel edge and may be positioned outside the channel as indicated on charts and nautical publications.

(3) Port hand marks indicate the left side of channels when proceeding in the conventional direction of buoyage. Beacons have green square daymarks, while buoys are green can or pillar buoys.

(4) Starboard hand marks indicate the right side of channels when proceeding in the conventional direction of buoyage. Beacons have red triangular daymarks, while buoys are red nun or pillar buoys.

(5) Preferred channel marks indicate channel junctions or bifurcations and may also mark wrecks or obstructions which the mariner, after consulting a chart to ascertain the location of the obstruction relative to the aid, may pass on either side. Preferred channel marks have red and green horizontal bands with the color of the topmost band indicating the preferred channel. If the topmost band is green, the mark serves as a port hand mark for vessels following the preferred channel proceeding in the conventional direction of buoyage, and as a starboard hand mark for the other channel. Beacons would have square daymarks, while buoys would be can or pillar buoys. If the topmost band is red, the mark serves as a starboard hand mark for vessels following the preferred channel proceeding in the conventional direction of buoyage, and a port hand mark for the other channel. Beacons would have triangular daymarks, while buoys would be nun or pillar buoys.

(6) The color schemes in this section apply to IALA Region B (Washington state).