Which of the following describes a 'buoy'?

A buoy is best defined as a floating device used to mark navigational channels. This is significant in maritime navigation as buoys serve several key purposes. They provide visual references for vessels, indicating safe passage routes, underwater hazards, or guiding vessels through channels. The presence of buoys allows mariners to navigate accurately, ensuring they follow predetermined paths while avoiding danger.

The other options relate to different concepts. A type of ship anchor refers to a device used to moor ships, while a weather forecasting tool pertains to instruments used for meteorological observations. A fish catching method may involve various techniques and equipment used to catch fish, none of which describe a buoy's function in navigation. Understanding the specific role of a buoy helps in recognizing its importance in maintaining safety and efficiency in marine operations.