A SMB is a useful device for your safety

The surface marker buoy (SMB) is an exercise that may seem complex. Yet if you were to have a permanent safety equipment on your scuba unit, it is a SMB. It allows you to signal your presence on the surface and has the advantage to provide a reference line for your safety stop.

Different kinds of SMB are available

There are many types of SMB : the long and thin are generally used for recreational diving. There are bubble-shaped parachutes, they are lifting bag that can rise to the surface heavy objects.

Most SMB are orange or red color. If you have a yellow SMB, you must know that they are normally used to signal an emergency. Another way to report an emergency is to inflate two orange SMB and stir them together.

To inflate the SMB, you have to blow sufficient air through the front slot. Some SMB are equipped with a direct-system connector. This will inflate your SMB while minimizing the risk of tangling.

Finally, remember that when you release your SMB, it will go to the surface. The air inside will expand. Your parachute could explode, especially if you inflate it at great depths. Some SMB are provided with a pressure relief valve as in BCD. Thus, when the pressure is too high, the valve will release excess air.

Which SMB to choose ?

I have a SMB with a length of 1.20m, orange color, with a pressure relief valve and with direct-system connector. I take into consideration the number of times I have to deploy it, it will not explode, if my octopus is already used, I can inflate it with the direct-system connector, a too long SMB would be tedious to withdraw.

Practice with your instructor

Since 2012, the use of a SMB is mandatory for PADI Open Water divers. During your training, I’ll teach you how to deploy a SMB in confined water and in open water. You should not buy a cheap SMB. As your dive knife, it is worth buying a good SMB with a valve, and keep it longer.