SMB / Safety sausage deployment at depth

[=C=]

So this is how to do it:



The thing is the spool needs to be ready, free, and clear. Stop if you have any extra line hanging.

Also, remember physics.. its doesn't take much air at depth to have a full bag at the surface. Finally, while there are a couple of techniques you can see on youtube the technique I like is to inflate orally as there little added buoyancy to manage. The air goes out of my lungs and into the bag...

O and ignoring the jerks.. I see you are PADI and would suggest a SAR specialty course from you instructor, its fun and will get you working on some skills before your trip.

 

[TSandM]

SMB deployment is definitely a skill and it takes practice. Small bags (the 3'/1m ones) can easily be deployed without much of a buoyancy issue . . . but although I say that, it took me quite a while to master it. I learned that I could tip a bit head-down and fin downward gently while inflating the bag, and then let go of it, and I didn't have to do any fancy buoyancy adjustments. For larger bags, the problem is bigger, and they are best shot at deeper depths, where you can put less air in them and still have them full on the surface.

The biggest risk of bag shooting is getting entanged in the line or the clips, and getting dragged to the surface. You can minimize that risk by making sure you are horizontal when you go to shoot the bag, and keeping your hands well out in front of you during the process. (Being vertical or near-vertical exposes a lot more of the front of you to the risk of entanglement.)

I highly recommend some practice in a shallow, controlled environment, like a pool or a shallow shore dive. (I practiced mine in 10' of water off Old Airport Beach in Maui!)

 

[dbulmer]

I think he is serious... and justifiably so. DSMB deployments account for far too many DCI incidents (according to BSAC reports). Deployment is a relatively complicated skill - so it is definitely a good idea to get some input and supervision when learning and practicing. Where that input/supervision is with an informal mentor or formally on a course, depends on your network and resources...

If more people got trained...then I am sure the DCI statistics related to DSMB use would decrease.

I disagree with you slightly.

I agree with your point about getting good input and supervision - it's essential.

Where I nitpick is your assertion about the DCI stats. I think you can be very well trained in blob deployment and still *ock it up. For me at least putting up a blob is about the most dangerous portion of the dive.

To reduce the risk with blobs you need the input and supervision, and then you need to get into the habit of putting up the blob as quickly as possible. I find that when I am slow in putting up a blob that is, when more often than not, it goes wrong.

It also really helps if you have a buddy watching you carefully - a second brain can help if it goes wrong

 

[=C=]

I disagree with you slightly.

I agree with your point about getting good input and supervision - it's essential.

Where I nitpick is your assertion about the DCI stats. I think you can be very well trained in blob deployment and still *ock it up. For me at least putting up a blob is about the most dangerous portion of the dive.

To reduce the risk with blobs you need the input and supervision, and then you need to get into the habit of putting up the blob as quickly as possible. I find that when I am slow in putting up a blob that is, when more often than not, it goes wrong.

It also really helps if you have a buddy watching you carefully - a second brain can help if it goes wrong

My 2c:

Quicker ≠ Better

Take time, watch depth, and when your ready launch the bag.

Im not too sure about the DCI assertion either... Have a source?

What I see with students is that they drop their heads and start to drop into the deep blue. They focus on the bag and forget about diving when the reality is you have tons of time for the SMB...

When it comes to buddies they tend to both try the SMB at the same time...

 

[Splitlip]

Another Tip if you are using an open bag. Transfer any air in your BCD to the bag using the inflator. Your Buoyancy and postion in the water column stay the same. When I had an open circuit bag, that's what I did. Stands the tube up nicely. And depending on how you are weighted, that might be all that is needed to get a full marker at the surface. But I still went negative and finned when I put the second stage in.

No you're not missing something, it's a good question. There are specific techniques for deploying an SMB and I studied some video clips when I wanted to get clarity on this topic. I can't remember where those clips are now but I'm sure you'll find some if you just search around on Youtube a little.

Here is what I do, and bear in mind, the DIR guys will probably identify any number of errors in this approach, but it works for me:

1. Get the SMB out of my BC pocket and unroll it. I have a 30m spool attached to the SMB.
2. Hold the spool between my thumb and middle finger of my left hand and blow the slightest amount of air into the SMB just so that it stands upright. This makes it easier when I'm ready to put the final amount of air into it and letting it run.
3. Hold the SMB with the index finger of my left hand, ready to let it go by just straightening the finger.
4. Look up to see if the path to the surface is clear.
5. Critical step: Inflate the SMB. I used to use my octo for this but are fairly comfortable with the procedure now so I just use my primary. If I'm on a solid surface I deflate my BC entirely but if I'm in open water I deflate my BC slightly. I then breath out just as I start inflating the SMB. I give it a proper blow of air for 2 or 3 seconds and then let it run.

I guess the important thing is to inflate the SMB as quickly as you can and not holding on to it any longer than is necessary. Inflating it takes only a couple of seconds so it shouldn't have much time to pull you up anyway. Seeing as I've deflated my BC just before inflating the SMB I'm slightly negative after releasing the SMB. I can compensate for this by just putting more friction on the spool with my hand until I've added air to my BC again.

All this deflating the BC stuff is a bit theoretical though because on most dives I try to weight myself such that I need very little air in my BC anyway. But even then, by inflating the SMB quickly and letting go of it as soon as I can, I usually don't get pulled up by it.

If I am negative after releasing the SMB I often don't even bother to get neutral again because I can just hang on to the SMB. This is probably not good practice but it's convenient. I rarely deploy the SMB if I'm not about to ascend (or have started my ascent already) so neutral buoyancy isn't all that important to me then. In fact, I often sit out my safety stop by clipping the spool to my BC D-ring and just hanging off the SMB.

Like I said, this is how I do it. I'm not a hugely experienced diver so please don't put too much value on this advice. I just thought I'd put it out there and you can take from it what you think is safe and can the rest.

 

[Splitlip]

If you are using an air-source (primary, secondary or nozzle) to inflate a larger bag, then you will gain buoyancy until the point you release it. The solution is to become slightly negative - use your breath control and, if necessary, fin to maintain constant depth - reducing your lung volume and finning power as you add air to the DSMB to compensate for the increasing buoyancy. Once released, you get neutrally buoyant again...and continue your ascent by reeling up..

Thank you Andy. I have gotten a ration of $hit for going negative and finning when I shoot. But somebody shoots virtually every dive I am on. And we have big ones. Getting a 40 -55 lb marker full from rec depths usually requires it.

 

[paddler3d]

If you get formal training or not on how to deploy a SMB from depth, or not, you're choice. It is a skill that is well worth practicing. Start off shallow and practice. Deploy, recover, deploy, recover. You can do that for a bit in shallow water, say 10ft or less, without risk of really hurting yourself. Instructors do these little bounce dives all day.

Then practice a bit deeper. Then add it on to the end of the Safety Stop. eventually add it at the beginning to the safety stop. Then practice shooting at deeper.

It isn't a hard skill. It is a skill that if you do it wrong, you can get hurt.

 

[Splitlip]

From a friend who got tangled in the line of a big bag.

"Scream! (keeps the airway open) and fin down if you can in order slow the exponentially increasing rate of ascent."

 

[EmptyTank]

I have never needed to shoot a bag so to speak. Why do people have so much trouble? It looks like a walking and chewing gum at the same time skill. I am not meaning to be glib so save the flames for someone else.

 

[Deefstes]

I have never needed to shoot a bag so to speak. Why do people have so much trouble?

I daresay, addressing the first sentence would answer the second. Go shoot a bag and you will notice that it is not as straight forward as it may seem.

I *think* the reasons it is so tricky (and I'm not saying it is dog difficult, just tricky) are:

- You're required to take your mind off diving and concentrate on something else. For experienced divers this part should be a cinch but this is exactly where many divers start forgetting about their buoyancy, proximity of the reef etc.

- You're involved in an exercise that involves exchange of air between different containers (cylinder, BC, SMB) fairly rapidly, which will affect your buoyancy and you need to be ready to deal with that.

- Unlike mask clearing which you can do as many times as you like until you get it right, shooting an SMB is an exercise that you have only one shot at. Once you've inflated the SMB and let go of it, it's gone. You can't reel it back in and try again. If you didn't add enough air to it, it will be limp on the surface until your dive is over.

- The risks involved in getting it wrong are significantly bigger than many other skills. If you get mask clearing wrong, you can't see for a while. If you get buddy breathing wrong, you just switch back to your own primary or octo. If you get shooting an SMB wrong, you lose the SMB or you get dragged to the surface.