What do the black and white marks on a buoy indicate?

The black and white marks on a buoy are indicative of safe water marks, often used to denote the center line of a navigable channel. These markings help boat operators safely navigate a waterway, especially in areas where navigation might be tricky or where the depth of water can vary significantly.

By signaling safe passage through the center of a river channel, these buoys assist in directing vessels and preventing grounding or collisions with underwater hazards. This is particularly crucial for maintaining safe navigation in busy or narrow waterways where other obstacles may not be marked as clearly.

In contrast to the other options, which refer to different types of navigation aids, the black and white markings are specifically tailored for guiding vessels through safe zones rather than providing warnings about the depth of water, underwater obstacles, or swimming restrictions.