What colors are cardinal marks in the IALA system?

In the IALA Maritime Buoyage System, cardinal marks are used to indicate the location of hazards and provide navigational guidance based on the cardinal directions: north, south, east, and west. The proper colors for cardinal marks are black and yellow.

Each type of cardinal mark conveys specific navigational information through its arrangement of colors and markings. For instance, a north cardinal mark features two black cones pointing upward and is black and yellow in color, advising mariners that the safest water lies to the north of the mark. Similarly, south cardinal marks would show a different combination of black and yellow, along with marking styles, to indicate the safest waters lie to the south.

Understanding the colors and meanings of cardinal marks is crucial for safe navigation, as they help sailors determine the safest channel to navigate. Other combinations, such as red and green or blue and white, correspond to lateral marks or other types of navigational aids, not cardinal marks. Thus, black and yellow are the defining colors for cardinal marks in the IALA system.