What does a cardinal mark with two upward triangles indicate?

A cardinal mark with two upward triangles indicates that the safest water is to the north. Cardinal marks are used in navigation to indicate the direction of safe water relative to the mark itself, which is especially important in waters where there may be hazards such as rocks or shallow areas nearby.

In the context of cardinal marks, the upward triangles (or points of the triangles) specifically signify the northern direction. This means that when navigating around a cardinal mark displaying two upward triangles, mariners should steer to the north to find the safest water. Other configurations of cardinal marks would point to different safe water directions (east, west, or south), but the two upward triangles indicate a clear direction to the north. Understanding these markings is crucial for safe navigation and avoiding hazards in maritime environments.