DSMBs- Essential Safety Equipment?

Several years ago whilst diving in the temperamental waters off South Africa’s east coast, I had the terrifying experience of becoming lost at sea. In the area where we were diving, it is local law for divers to dive with a buoy line or an SMB- a surface marker buoy that remains on the surface throughout the dive and lets the skipper know his divers’ location even in strong current or choppy seas. Typically, the divemaster will hold this buoy line for the duration of the dive, and it is the rest of the group’s responsibility to stay with the line. On the day I got lost, however, the current was so strong that my buddy (who was holding the buoy line) never made it down to the dive site. Instead, she was swept off over the reef and before I knew what had happened, we were separated.

We both surfaced immediately- she, with her fluorescent orange buoy, got picked up by the boat straight away, while I, with nothing, watched helplessly as the boat went looking for me in completely the wrong direction. There was a big swell that day, and the skipper hadn’t a hope of seeing my small neoprene-covered self bobbing between the waves. I tried shouting and waving my arms, but to no avail. I started to feel the panic rising in my chest- here I was, in rough, shark-filled waters, unable to attract the boat’s attention and (at least in my mind), about to be abandoned at any moment. Fortunately, after almost an hour, the boat found me by chance and no harm was done. However, that experience could have been avoided if I’d been carrying my own personal DSMB (delayed surface marker buoy), and since that day I will not dive without one.

Typically, a DSMB takes the form of a brightly coloured tube connected to a reel, which when rolled up can fit into a BCD pocket. It is designed to be deployed during the safety stop, to give dive boats time to locate their divers before they surface, and equally importantly, to warn boat traffic of the divers’ presence. In areas where the use of an SMB or buoy line is required, a DSMB should not be considered as an alternative, but rather as an additional safety requirement that minimises an individual’s chances of becoming lost or being hit by a boat in the event of separation from the group. They are particularly necessary in areas with strong current, on days when surface conditions are less than ideal, and in places with a high level of boat traffic. When purchasing a new DSMB, make sure that you are fully familiar with how it works- as well as coming in different colours and sizes, inflation mechanisms differ from one DSMB to the next.

Some DSMBs are open-ended and require inflation using your alternate air source, while others are inflated orally or with the help of the low pressure inflator hose via a valve. Knowing which method applies to your DSMB and how to execute it safely and effectively is the key to successful use. Similarly, divers must take care not to become entangled in their DSMB line, and must remember to unclip the reel from their person before inflation to avoid being dragged to the surface along with the marker. When choosing a DSMB, consider the specific conditions in which you intend to use it, as well as your own proficiency as a diver. For example, open ended DSMBs may be a safer option if you are not keen on removing your regulator underwater to orally inflate the tube; equally, experiment with different reels to find out which variety you are most comfortable with.

When used properly, a DSMB should be considered as an essential piece of safety equipment. Particularly in the case of diver separation, it allows a potentially frightening and dangerous situation to be safely mitigated- which is why every diver should carry a DSMB in their BCD pocket. In all likelihood, only one person in a buddy pair or group will have to deploy their DSMB at the end of the dive; if following a buoy line or SMB, perhaps no one will need to use their personal marker buoy. However, if every diver carries a DSMB, everyone is protected in the event of the unexpected happening- and, the group has backup if a problem occurs with the primary surface marker buoy. Don’t wait until you too have been lost at sea to buy a DSMB- find one that’s right for you, practice with it and carry it with you on every dive.

Article by Jessica Vyvyan-Robinson. Jessica writes for ScubaDiveDestinations.com as well as for Scuba Dive Tourism and Marketing.