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Thoughts on SMB use

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There's a few tricks I've picked up over time teaching people that I thought I would share about the risks involved in putting up SMB's, and how best to avoid any problems.

 

Procedure and equipment selection

I'm sure I am by no means alone when they admit they have tried to put together a reel and SMB only to see the thing disintegrate into it's component parts in front of my eyes, much to the amusement of my buddy. A relatively deep sea dive is not the place to try out a poorly maintained piece of equipment, least of all a bag of air that is goig to shoot up to the surface Despite what some people might tell you, there really is no right and wrong when it comes to selection of SMB, spool or reel. However, make sure whatever you are using is well maintained, and that your are familiar with it's use, so that putting it up becomes second nature.

 

Speed

This is something everyone does, especially if a little stressed. It's like they feel the need to get the process of putting up the SMB as quickly as possible. This isn't helped by people on the internet saying things like "wow, it takes you 37 seconds to put up an SMB, I only need 25". This creates a culture of stress around the task. People feel they should be able to do it in a speed equaled only by superman. Why? What's the hurry? If you rush a task, two things happen.

Firstly, you will make mistakes. I'm writing this article at break-neck speed. There WILL be spelling mistakes in it. If I'm smart, I'll slow down at the end and go through it slowly. When you approach a task slowly and methodically you are far less likely to make a mistake. This is as true underwater as it is above the water.

The second thing that happens when you rush is that you generate stress. If you are stressed it is likely you will become task fixated and forget about other things, such as buoyancy control. This is an obvious issue. Slow down. What's the rush. It really doesn't matter if it takes you ten seconds or three minutes. Just chill out and do the task. Try doing it as slowly as you can. Then do it again and try to take an extra 20 seconds. Then take an extra 10 seconds. Eventually you'll have to do a bit the task. stop for a bit, then do a bit more. It'll feel wierd, but you'll be amazed just how much stress this removes.

 

Task fixation

Leading on from stress, it is all too easy to become task fixated when putting up an SMB. It's easy to spot. I can wave my hands frantically in front of students pretending to drown, and they will happily fail to see me because they are so fixated on putting up the bag. you put an SMB up when you are near the end of the dive. This is when problems such as cold, out of gas, etc are most likely to happen. So just because you are putting up an SMB doesn't mean that you have an excuse to ignore your buddy.

Slow down, and keep your eyes on them rather than the SMB. Keep the focus on staying in position and in contact with your buddy, rather than putting the SMB together quickly and smoothly. Make that the bit that has to wait.

 

Entanglement

Getting entangled in line on a wreck is a bit disconcerting, but usually easily resolved if you remain calm and let your buddy untangle you or cut you free. On the flip side, getting entangled in SMB line when you are deploying an SMB can go from being relatively annoying to terrifying to downright extremely dangerous within a few short seconds.

You are holding a bag of gas in front of you, a bag which is becoming more buoyant every inch it goes up. The worst case scenario is that you end up entangled, or entangle someone else, which means you will in all probability send them uncontrollably to the surface. Which is, for clarification, not a good thing. This is easily overcome. Hold the SMB at arms lengths in front of you, making sure you control all slack line in the water. When you send up the SMB be sure to get an OK from your buddy first, so they know you are about to inflate a bag of gas in front of them.

Finally, make sure you look up. Don't put so much gas into the SMB that you lose control of it. I like to be able to hold on to an SMB so if there is a sudden problem I can just hover there and wait before letting go. If your solution means you have to let go of it in 2 seconds or get dragged screaming to the surface then maybe you need to rethink your solution. A crack bottle SMB is a very nice piece of kit when inflated slowly, or just inflated as much as it needs to be. I only have a problem with them when people crack them wide open and have to get the things away before they fully inflate in a second or so. That to me, is not well thought out.

 

Loss of buoyancy control

I have video of people continuing to assemble an SMB and then looking all confused when they try to send up the SMB and it doesn't go anywhere. The reason for this is because they are actually already on the surface. This happens for two reasons.

Firstly, if they are inflating the bag orally, they take a whopping great breathe to blow into the bag. This is a side effect of the desire to rush and get it over with. You can easily avoid this problem by simply taking a normal breathe and putting it into the bag. You should then be able to put another one in if you need to. Remember if you are putting a bag from 21 metres, you only need to fill a third of it in order for it to fill up on the way to the surface. Physics will deal with the rest. If you are deeper than 21 metres, then you need even less.

The second reason people lose buoyancy control is that they become stressed and their breathing pattern changes. They then slowly drift up towards the surface. This is, again easily avoided by slowing down to reduce the stress, and by using their buddy as a buoyancy reference if not other buoyancy reference exists for them to look at. Stay in eye contact with your buddy. He or she will remain neutrally buoyant - that's their role. That's all they have to do. All you have to do is put the bag up and keep an eye on them. By forcing yourself to use them as a buoyancy reference you keep the two of you together and reduce your own stress load as there is no need to constantly glance at your own depth gauge as well as put up the SMB.

The flip side of all of this, of course, is on the way up, where I have a really funny video of three people hovering at three metres, and then winching their poorly inflated bags down to them. Whilst it does liven up the coaching with a good laugh, it does demonstrate that the divers were relying on the bags for buoyancy control. Whilst this is not a problem most of the time, it could be an issue if some emergency forces you to let go of the SMB. This is why you read reports of people having an problem during and ascent, dropping back down to the wreck and then sorting it out there. Control this by just holding the line for a few seconds rather than the reel, and see what happens. If you suddenly start dropping, then correct your buoyancy for the depth you are at. You will relax, and use far less gas.

 

Confusion

I dived with someone a few weeks ago that told me he had just purchased this new SMB and wanted to try it out on the dive we were doing, which was a 30 metre dive. Now many people will consider 30 metres to be a relatively shallow dive, but the word is relatively. Being hauled to the surface by an unfamiliar piece of equipment from 30 metres is still going to hurt. A 30 metre sea dive is not the place to try out new equipment. Try it in a swimming pool. Find out what can go wrong, and there is always something that can go wrong - no equipment configuration is perfect, whatever you may read on the internet.

 

Summary

So. Familiarise yourself with your SMB and the process of putting it up. Slow down to reduce the stress. Keep with your buddy by watching them. Keep breathing normally and maintain your depth. And remember - if you feel nervous about putting up an SMB, the solution is to practice in a safe, controlled environment.

Dive safe.

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Gareth Burrows is a GUE Instructor trainer, and a personal diving coach for recreational and technical divers of all levels, specialising in improving buoyancy control, trim and stability, in-water confidence, and ascent management. He has trained with PADI, TDI, IANTD and GUE as well as serving as a DO in a BSAC branch. He has been diving cold water wrecks in Europe and around the UK for over a decade, and can usually be found diving out of Brighton, Portland or Plymouth. He is qualifying later this year as a cave diver and looking to become a GUE tech1 instructor in the 18 months. He has trained or coached hundreds of divers from newly qualified open water divers, to course directors and technical instructors.

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