In your initial dive-training course, your instructor might have taught you how to inflate a surface marker buoy (SMB) on the surface. For those who don’t remember, a SMB is an inflatable buoy. It’s attached to a line, and divers use it to let their boat know their position while still underwater. Even it may not seem like a skill you’ll need to know early in your diving career, it absolutely could be. So it’s important to know how to inflate one.
Commonly known as a safety sausage, this device takes up only a small amount of space in your luggage. Once underwater, you’ll carry it either in your BCD pocket or clipped to your jacket. It can be crucial when it comes to your safety. You will deploy some SMBs from underwater; these are known as Delayed Surface Marker Buoys (DSMB). You will typically use these at the end of drift dives to let the boat know where you are. You may also use them in areas with boat traffic to make sure you are ascending safely.
Deploying one underwater will take a bit of practice. Reels or lines may vary from basic to advanced systems. They may vary in length from 16 to 328 feet (5 to 100 m). Before buying a reel or a line, ask your dive buddies what they use and why they like it. Don’t forget that the inflatable tube itself is a signaling device. Choose one that’s big and bright enough for a boat to spot it from a distance. Some SMBs are be semi-closed and feature a dump valve; you’ll need to orally inflate others. These small features can make a difference, so try your equipment on dry land before you take it diving. Underwater, practice deploying it as often as you can with assistance from a dive buddy or your dive guide if necessary.
When deploying a surface marker buoy from underwater, the air you put into it will change your buoyancy, so you want to be able to control your position in the water during the DSMB launch. Make sure that you don’t entangle yourself or another diver in your line.
Deploying a marker on the surface is quite easy. Blow air inside the SMB with your mouth or regulator, and you’re all set. Despite this, be sure to practice, as rough surface conditions will hamper your efforts, and you don’t want this to be the first time you’ve deployed your buoy.
Recreational divers may think carrying a surface marker buoy is pointless since your dive guide is most likely carrying one. Or you may be diving in an area that you know. But as we know, sometimes dives do not go exactly as planned. What if the current picks up and you drift further away than expected or cannot come back to the mooring? What if you get lost and the boat is too far away to spot you? What if a problem arises underwater and you have to come up earlier than expected? What if you and your buddy separate and you must ascend alone?
These unplanned for issues, and more, can come up on any dive. And while they are not a huge problem in and of themselves, each of these scenarios can become a difficult situation if you ascend without a visible device. Being able to signal from underwater or when you get to the surface will hugely alleviate any stress or danger caused by the situations listed above. So buy a surface marker buoy, learn how to use it, and bring it on each and every dive.