What signals the presence of a dangerous wreck in the IALA system?

The presence of a dangerous wreck is signified by a wreck mark buoy in the IALA system. This type of buoy is specifically designed to indicate a hazard to navigation, such as a submerged or partially submerged wreck. The intention is to alert mariners of the danger to avoid potential collisions or grounding incidents.

A wreck mark buoy typically has distinct characteristics, such as specific colors and shapes, that help mariners easily identify it as a warning of a dangerous underwater obstacle. This buoy plays a crucial role in ensuring safe navigation in waters where wrecks may pose a risk.

In contrast, other types of buoys serve different functions. A lateral buoy indicates the navigable channel's sides, guiding vessels along safe routes. A safe water buoy indicates that there are navigable waters all around it and does not signify any danger but rather reassures mariners of safe passage. A special purpose buoy is used for specific purposes, such as marking a fishery or a mooring area but does not indicate the presence of a danger like a wreck.

Understanding these distinctions is essential for mariners to effectively interpret buoy markings and ensure navigational safety.