Cardinal buoys are used in conjunction with a compass to indicate to mariners the location of the safest water in which to navigate. They are called Cardinal Buoys because they follow the cardinal points of the compass (i.e. North, South, East and West). Cardinal Buoys are black and yellow in colour and it’s the orientation of the black colour that points to the location of the safe water. The orientation of cones placed atop each buoy also provide this information.