What is the function of a surface marker buoy (SMB) in diving?

The function of a surface marker buoy (SMB) is primarily to signal the diver's location to surface support and enhance visibility during ascent. When a diver uses an SMB, it provides a visual reference point for boats, support teams, and other divers, indicating where the diver is underwater, especially during ascent or safety stops. This is crucial for safety, as it helps prevent collisions with vessels and ensures that the diver can be easily located in case of an emergency.

In addition to signaling, the buoy also increases visibility, allowing surface support to monitor the diver's ascent trajectory and provide assistance if needed. The use of an SMB is a standard safety practice in diving, as it helps manage the inherent risks associated with underwater activities.