What does the term "buoy" refer to?

The term "buoy" refers to a floating device that is specifically designed to mark channels and hazards in the water. Buoys serve several critical purposes in navigation, including guiding vessels safely through narrow channels, indicating the presence of hazards such as rocks or shallow areas, and assisting in the overall management of waterways. They are often equipped with various colors, shapes, and lights to convey important information to boaters about their surroundings. This helps ensure safety on the water by providing visual cues for navigation.

The other choices do not accurately describe what a buoy is: a type of anchor is meant to secure a vessel in place; a navigation system typically involves a broader technology or method for helping navigate, often including electronic components; and a personal flotation device is a safety item designed to keep a person afloat in water. Each of these alternatives serves a different, specific function related to boating and safety.