Surface Marker Buoy

From Free net encyclopedia

Template:Multiplemergefrom A Surface Marker Buoy, SMB or simply a blob is an inflatable buoy used by SCUBA divers, with a line, to mark the diver's position to their surface, safety boat while the diver is underwater. Image:Surface marker buoy.JPG SMBs are inflated on the surface before diving to mark the diver's position during a drift dive or night dive so the dive boat can follow the divers, or where there is boat traffic making diving more hazardous.

Divers need to consider some configuration options and features when using SMBs. A closed SMB, with a valve through which the user blows, is likely to be more reliable, by remaining inflated, than an open ended buoy or a delayed buoy which seals itself as it inflates.

To avoid losing the reel, a lanyard attaches the diving reel to the diver. This lanyard can clip to the buoyancy compensator or go around the wrist. Alternatively, the lanyard can be long enough to float above the diver and stay out of the way. If the lanyard clips to the buoyancy compensator, the user should take care to release if there is surface boating activity, as boats may drag divers up by their SMB reels.

The DIR diving philosophy considers unsafe any attachment to equipment or objects which end above the water surface, due to high risk associated with dragging the diver upwards in spite of their decompression obligation or maximum ascent speed limit.

A specialised form of SMB is the decompression buoy.