Which marker indicates controlled areas with specified speeds?

The circle marker is specifically designed to indicate controlled areas where certain boating regulations, including specified speed limits, are enforced. This type of marker typically conveys vital information about the waterway rules that boaters must adhere to in that particular area. The circular shape draws attention and signifies that caution is needed, often alerting operators to a restricted speed zone, thereby ensuring safety within that area.

Understanding the symbolism of markers helps maintain order and safety on the water, allowing boaters to navigate responsibly according to local regulations. Other markers, while also important, serve different purposes such as indicating hazards, traffic patterns, or navigation aids, but do not specifically denote controlled speed zones.