Object marked with the speed limit, sometimes NYT Crossword Clue

Think of something that floats and guides, especially near the shore.

A ???? is a floating object anchored in a body of water to mark channels, warn of danger, or indicate a specific location.

The clue plays on the dual meanings of 'object' and 'speed limit.' A '????' is an object found in water that can be marked with speed limits for boats, similar to how signs on roads indicate speed limits for vehicles.

Harbor bobber, Bobber in a lake, Bay bobber, Nautical marker