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Surface Marker Buoys

Surface markers buoys (SMBs) can be used in many diving scenarios; they can be used to warn boats of the presence of divers or to maintain communication with the surface support team.

SMBs remain at the surface for the duration of a dive; the diver controls the line leading to the SMB using a reel. It is recommended that SMBs clearly indicate that there are divers below, and they should ideally include the international Flag ‘A’ as part of their design.

A Delayed Surface Marker Buoy (DSMB) can be useful in some situations as an alternative to an SMB. The DSMB is initially carried underwater by the diver in a deflated state, then at some stage towards the end of the dive, the diver deploys the DSMB while still underwater, using a reel to feed out a line. This line can then be used as an ascent aid, and the buoy can show the support team the location of the divers.

DSMBs can also be used to indicate an emergency situation. Some divers carry two DSMBs of different appearance, with one being used routinely, and the other only being deployed to indicate an emergency.

The following procedures are recommended for the use of Delayed Surface Marker Buoys (DSMBs). These procedures should be thoroughly discussed with and understood by all team members prior to undertaking any dives. This includes all divers and members of the surface party and boat skipper.