cardinal marks

Buoys of standardized colors, topmarks and lights whose placement alone or in a pattern corresponds to the divisions of a compass.

North

The north cardinal mark is composed of two topmarks with both tips pointing upward.

white light

White flashing light whose flash pattern serves as a cardinal mark at night.

Northwest

West

The west cardinal mark is composed of two topmarks placed tip to tip.

Southwest

safest water

Navigable water is deep enough that it is safe to proceed.

South

The south cardinal mark is composed of two topmarks with both tips pointing downward.

danger

Buoys signal shallow waters, a submerged object or an object posing a hazard to a boat or a ship.

Southeast

East

The east cardinal mark is composed of two topmarks placed base to base.

Northeast

topmark

Metal cone-shaped part atop a buoy that serves as a navigation aid during the day; its position signifies various meanings.