One of the best emergency signaling devices that can be carried by divers, and we recommend that every diver carry on any open water dive, is the inflatable signaling tube also known as a Surface Marker Buoy (SMB), or Delayed SMB.
With the increasing number of high-profile reports of lost divers and serious surface accidents involving boats, the importance of brushing up our scuba safety skills has only been heightened. For those who have never deployed an SMB before, but have watched a fellow diver or instructor shoot one up, you may think there's not much to it. However, this couldn't be further from the truth.
The most common problems inexperienced divers face with deploying a SMB are tangled reels, divers attaching themselves to reels, or divers not being able to control their buoyancy during deployment. All of these problems can lead to pretty serious ascent rate issues and ultimately increased risk of decompression sickness.
Though often referred to as the same, SMBs and Safety Sausages do differ. Safety Sausages are deployed at the surface for signaling. A Surface Marker Buoy (SMB) is deployed from depth, and often features an over-pressure relief valve (OPV) as they are closed tubes.
Surface maker buoys or SMBs, are big, inflatable tubes that mark a diver's location. They are brightly colored and sometimes feature reflective materials for additional visibility. SMBs are very useful and could potentially save your life — but only if you know how to use them.Surface marker buoys (SMB) are effective when deployed underwater as intended. This gives the boat or divers at the surface a heads-up that you are making your ascent. That's why we think deploying it on the surface, or using a Safety Sausage that can only be deployed on the surface, is stupid. After all, how did you safely get to the surface if there is boat traffic in the area?
While the features of the Surface Marker Buoy may differ according to the type you're using, here's a general step-by-step guide to deploying a SMB from a depth.
SMBs can be inflated at the surface but are truly effective when deployed underwater. This gives the boat a heads-up and allows it track divers prior to them surfacing. In many instances this gives the boat time to get into position to pick up divers as soon as they hit the surface, something that is especially useful if currents are strong, or if emergency assistance is needed. It also enables you to warn other boats that you're there and that they should keep clear. Many technical divers deploy their SMB at their first deco stop. Most recreational divers deploy it from their safety stop. We recommend you deploy your SMB before you start your ascent. This means you're doing it from a deeper point which makes it easier to control your buoyancy, plus you don't have to get as much air into the SMB. It also tells the dive boat you're starting your ascent.
Before you begin, ensure you are neutrally buoyant. Make sure your buddy and any other divers are far enough away from you to avoid the possibility of them becoming entangled up in it. Also check to see above you that the SMB will not come into contact with another obstruction, diver, boat, or take out a group of open water students above you!
Let your dive buddy know what you're about to do. Signal them, 'You, Watch, Me, Shoot' and wait for them to repond with 'Okay'. That's also the signal to tell them to maintain their depth, so that you can work off them, instead of you having to monitor your own depth.
Take out your SMB from where you stored it. Many people like to store their SMB and reel in a BC pocket. We prefer to have the reel clipped to a D-ring on the BCD, while attached to the BCD which is held on the side of the BCD in a bungee cord loop. It's ready to go. However, if the reel line isn't already attached to the SMB, you'll have to attach it. Generally, most SMBs have a small D-loop located on the bottom of them. You need to attach the SMB lower D-loop to to a loop in the line from the reel. Once through, unreel just a little line, to make sure the loop in the line isn't tangled round the reel. Look up and check that there are no obstructions and ensure you aren't entangled in or attached to the SMB or line.
Once cleared to deploy, wrap up the reel, line and any excess SMB material into one hand. Making sure that no materials like the line are wrapped around your fingers or dive gear and the reel is unlocked. Holding the SMB and reel with the left hand, inflate the SMB.
How you do this depends on the SMB — but no matter what method you use, it's important to practice! Many SMBs have openings at the bottom where you can vent air from your regulator to fill them up. You can do this either by purging your occy underneath the SMB or holding the opening above your head to catch your exhaust bubbles — there is no need to take your primary out of your mouth! SMBs with oral/low-pressure inflators can be filled using your BC inflator hose, just remember to replace it back on your BC when you are finished! If you use an SMB often, you can also attach a secondary inflator hose to your regulator's first stage so you don't need to undo your BC inflator hose every time. If you need to inflate the SMB orally, remember to save enough breath to clear your reg between breaths and to never hold your breath. At depth, a small puff of air will suffice to hold your SMB up at the surface, because the gas will expand as it ascends. This is why we prefer to shoot from the bottom of the dive.
Keep a solid grip on the reel, but don't hold onto the line or SMB after it begins to ascend or you may be pulled up with it in a rapid ascent. If you have trouble staying down, try making yourself slightly negatively buoyant, or try adding less air to your SMB. If the reel gets caught and starts to pull you to the surface, let go of it. Never attach yourself to the reel. Once it reaches the surface make sure to hold the line taut so the SMB stands straight up in the water.
When the SMB hits the surface, wind back the line on the reel and apply some extra tension on the line in order to make the SMB stand straight up. Make your way to the surface while reeling in the line so it stays taut. Slack in the line can cause the SMB to fall to the side and allow air to escape. Ascend at a safe rate and don't forget to do your safety stop.
When you reach the surface continue to pull down on the SMB so it remains upright until the boat is ready to pick you up.
This video shows an example SMB deployment. Note the 'You, Watch, Me, Shoot' hand signals at the beginning. The diver is using a finger spool instead of a reel, and inflating the SMB orally, which are both harder to get right.
SMBs can be used to signal the need for a boat pick up, as a distress signal, a marker of a location, or to indicate the need for additional air on long decompression stops. Red or Orange is the standard colour for a SMB. A Yellow SMB is supposed to be an emergency signal. Red/Orange can be better seen in some weather conditions, and Yellow in others. That's why we like using a SMB that's Red/Orange on one side and Yellow on the other.
Practice deploying your SMB in a controlled environment, or pool, if possible the first time around and then on all your dives to get proficient with the skill. But make sure to let any shore based bystanders know that you're only training, so they don't misinterpret it as a distress signal and start calling for help.
With this self-inflating SMB you can make deploying your SMB really easy!
For teaching DSMB deployment AP Diving has manufactured a specially designed small DSMB.
For more SMB options, please see Surface Marker Buoys (SMBs).
Deploying your SMB is an important skill not to be overlooked or ignored. Once you're proficient, you'll deploy your SMB often. Dive Safe!