What purpose do special marks serve in the maritime buoyage system?

Special marks in the maritime buoyage system have a specific purpose related to providing information that is not covered by the other categories of navigation marks. They indicate areas for special significance, including but not limited to speed restrictions, mooring areas, and other navigational advice that may not pertain directly to traditional navigational aids.

These marks are particularly important for managing traffic in busy waterways or in areas where additional regulations apply. For instance, a special mark might signal a speed limit zone where vessels must slow down due to environmental concerns or to ensure the safety of other vessels or marine life. Such distinctions help to facilitate safe navigation and compliance with local maritime laws, offering valuable guidance to mariners who may not be familiar with the specific operational regulations in that area.

In contrast, the other options represent different categories designed to address navigational hazards and provide safe passage, such as identifying safe waters or marking hazards. However, special marks are unique in their focus on regulatory and advisory information beyond basic navigation.