What is the function of a Surface Marker Buoy (SMB) during a dive?

The function of a Surface Marker Buoy (SMB) during a dive is primarily to indicate the diver's location on the surface for visibility. When deployed from underwater, the SMB rises to the surface and remains buoyant, making it easily visible to boats or other divers above. This visibility is essential for safety, as it allows surface vessels to avoid the diving area and helps to facilitate coordinated pickup when the dive is completed.

While navigation can be an important aspect of a dive, an SMB is not primarily designed for that purpose. It is specifically intended to mark a diver’s location. The buoy does not significantly provide extra buoyancy for a diver; its design is more about marking position rather than contributing to the overall buoyancy system of a diver’s equipment. Additionally, the primary function is not to signal to other divers to come up, although it may serve that purpose incidentally. The main goal remains enhancing safety through visibility.