Diver Safety – Surface Marker Buoys


During a Scuba dive, the current is unusually strong and pulling your dive team in the wrong direction. It is difficult to swim against a very strong current, so you will have to go with it, but, by the time that you safely come to the surface, you will be so far away from the boat that the captain and crew will not be able to see you. What should you do next?

What is an SMB? A Surface Marker Buoy (SMB) is a sausage-shaped buoy used by scuba divers to indicate the diver’s position to the dive boat. An SMB can be inflated at the surface but it is most effective when deployed underwater. This allows the boat crew to track the divers prior to their ascent and gives peace of mind to all participants. 

An SMB can be towed along for the whole dive but this is not always practical. The preferred option is to deploy the SMB just before you start to ascend. Both methods can help maintain the divers’ depth and this can work really well during a safety stop.

SMB Surface Marker-Buoy Diver Safety
SMB Surface Marker-Buoy Diver Safety

Why an SMB could save your life.

You have no doubt heard some horror stories of divers getting left out at sea, but If those divers carried a Surface Marker Buoy (SMB) then they would have a better chance of being spotted by a boat. It is difficult to see a diver bobbing on the surface from a distance but a bright orange SMB upright in the water is much easier to locate. Through a pair of Binoculars, the SMB may appear as an orange dot in the distance but without an SMB it could be too difficult to see anybody at all. If you are on the surface at the end of a night dive you can shine your flashlight into your SMB from underneath which will illuminate the whole thing.

Practice makes Perfect.

Deploying your SMB at the end of a dive can take a bit of practice and something you will master over time. Inflating an SMB is now included as a requirement of the PADI Open Water Course. Usually, the best depth to deploy your SMB would be at 5 meters during the last few minutes of your dive. Most SMBs have openings at the bottom where you can add air to fill them up. You can do this by purging your alternate air source into the opening of the SMB.

Sending your SMB to the surface in a smooth manner whilst maintaining neutral buoyancy certainly does take some practice. And you will need to do all of this whilst checking the surrounding area and most importantly making sure your dive team is all ok.

SMB Surface Marker-Buoy Diver Safety
SMB Surface Marker-Buoy Diver Safety

Surface Marker Buoy (SMB). An SMB is an inflatable signal tube that every diver should carry in their BCD pocket. If you become separated from your dive team or you are caught in a strong current then you will have to deploy your SMB to let the dive boat know that you are ok and so they can track you from the surface. If you ascend a long way from the boat without an SMB it will be difficult for them to see you. Get yourself a Surface Marker Buoy, even a cheap one is good enough.

The basic use of a Surface Marker Buoy is now taught to beginners during the PADI Open Water Diver Course. The student diver will have to demonstrate how to inflate an SMB either at the surface or underwater. The surface marker buoy is an industry-standard safety item that all Dive Leaders must carry. It’s unlikely that you will use it often but it’s there just in case and it will give you peace of mind.

How to Deploy a Surface Marker Buoy.

Check Your dive team is ready to ascend, check that your SMB is attached to your finger reel, and check that the overhead area is clear.

Keep a loose grip on your finger reel and when you are ready, just add a very small burst of air into the opening at the bottom of your SMB. This will allow it to unfurl into an upright position in front of you.

Next, add a larger burst of air and let the SMB go to the surface. If this is done correctly the finger reel should unwind in front of you as the SMB travels upward.

After the SMB reaches the surface, make a firm grip on your finger reel, and keep the line tight by gently pulling downward.

You can now begin to ascend whilst reeling in the line. Keep the line tight so that the SMB remains in an upright position. When you reach the surface, signal to the boat that your dive team is all ok.

Buddy Checks.

During your pre-dive safety checks did you ever think to ask if your dive leader has an SMB? All dive leaders should carry an SMB and even better if every diver carries their own. An SMB Combined with a finger reel that is easy to use, is both lightweight and small. It is an inexpensive purchase and it could save your life.