What navigational information is provided by a cardinal mark?

A cardinal mark is specifically designed to indicate the direction of safe water relative to the mark itself. The information conveyed by a cardinal mark is primarily determined by its shape and color, which indicate whether the safe water is to the north, south, east, or west of the mark. Each cardinal mark has distinct visual characteristics—colors (yellow and black), the arrangement of those colors, and specific point shapes (such as upward or downward pointing triangles) that provide essential guidance for vessels navigating near hazards.

This navigational aid helps mariners understand the safest passage around potentially dangerous areas by providing clear visual cues about where to steer their vessel. The cardinal system is not used to provide information about anchorages, water depths, or currents; instead, its sole function is to ensure safe navigation in relation to the mark's position and the cardinal directions it represents.