Inflating DSMB from exhaled gas

[tbone1004]

Why not? Works perfectly and reg is far from the buoy.

There is a significant entanglement risk by doing this, isn't there? Already saw some people going up with reg attached to the buoy/line.

why would you exhale into the opening when you can blow into the inflation tube? A lot less efficient to try to blow into the bottom of the buoy because you will likely waste gas out the edges.

I wouldn't say the entanglement risk of inflating with the regulator is significant. There should never be anything that actually attaches the buoy to your body once it is inflated. If they went up with the buoy, they didn't make sure the buoy was clear before inflating it.

One extra step that I teach that helps prevents the elevator ride.
At 4:10 in the video, you can see Achim start to inflate the dsmb. Especially with large DSMB's, when in current, if there is a light or mirror on the dsmb, etc etc you put a small puff of gas into the dsmb. All this does is cause the top of the buoy to rise just enough to keep the buoy controlled instead of flapping in the proverbial wind. It won't cause anything to go uncontrolled to the surface as it only has just enough lift to keep itself vertical. At this point, you can ensure that the spool or reel is clear, check above you, then finish inflating the buoy. This can be done with any inflation method you choose. I teach our students to inflate orally, with a power inflator on the inflation nipple, and with a regulator, but they only do the regulator/inflator once and the rest of the practice is done orally. I don't like the power inflator because you usually need two hands to inflate them which means your spool/reel is either dangling or clipped off which is bad. I don't like the regulator because it's annoying and requires an open bottom DSMB and I don't like those. I have one, but I don't like them.

The bigger concern with people taking an elevator to the surface usually comes when they have a buoy that really is designed for surface use. These are usually the 2m+ in length and also usually have a big strap at the bottom of them which allows you to step on them to keep them vertical. Great for when you get to the surface and need someone to come find you, but really ungainly to shoot from depth. The big strap at the bottom allows a lot of potential for things to get grabbed because it's a loop, and it's compounded by the fact that you almost have to inflate these with a regulator or power inflator because of their volume. I say almost because if you're deep enough you don't have to, but who wants to shoot these things from 100+ft?

If I'm in OW, I have a 1m little buoy from @cool_hardware52 that I love because the DSS model is really tiny, still has solas tape on top, but can be fully inflated in less than one breath. Slick little buoy. Great for letting a boat know where you are for drift dives, send message up from deco, etc etc.
The big one I have is a 2ish meter behemoth that is the "oh sh!t I'm lost, come find me" buoy and that doesn't get deployed from depth. It is open bottom, has a big loop thing so you can step on it, etc. but it's not one that I plan to deploy from depth

 

[uncfnp]

The easiest way to inflate a small buoy is just to exhale a breath into the inflation tube.

Larger DSMBs have several options that depend to some extend the way they are constructed. Some are open ended, some are closed, some have oral inflation tubes, some have the option to connect to inflation hose. My favorite DSMB has all options.

For me orally inflating a larger buoy isn’t a good choice, especially from the safety stop. My preference is inflation at depth and through an open bottom with my second stage. I have tried the head tilt, exhaust bubble maneuver but like the op I can never hit the vent. There is at least on SBer that write that he prefers this method. I think may @stuartv ?

 

[boulderjohn]

When I got my TDI Advanced Nitrox certification, my instructor inflated his bags by simply holding the bottom opening over has regulator as he exhaled. He had no trouble doing it. I could never get the hang of it. That was a while ago, and I think the difference was that the bottom of his bag was fully open, while mine had the one way valve system now used on pretty much all such bags today, meaning I had a much smaller opening with which to work.

I use the tube these days.

 

[boulderjohn]

Adding to my last post....

Back when I got that certification, pretty much everyone where I was diving used those open ended lift bags as a surface marker during their open ocean ascents. Today pretty much nobody in that area does that--DSMBs with inflation tubes are the norm.

 

[Lorenzoid]

My Fundies instructor encouraged me to inflate using the reg exhaust. I think his point was that keeping a reg in one's mouth rather than removing the reg to blow into the tube provides one less chance for things to go wrong. Or maybe stated another way, all other things being equal, it's preferable for a reg to be in one's mouth at all times rather than not in one's mouth.

Later, it became clear to me that few people inflate their SMBs that way. The GUE videos show the oral inflation tube method.

 

[Edward3c]

Join a BSAC club and they’ll show you various ways to inflate a DSMB. It’s all part of core training, nothing complex about it.

 

[BlueTrin]

Join a BSAC club and they’ll show you various ways to inflate a DSMB. It’s all part of core training, nothing complex about it.

I am part of one, just wanted to use my pool time to practice on my own

 

[stuartv]

I do indeed inflate mine by catching exhaled bubbles from my reg.

The only SMB I normally use is a 6' DAN SMB. I.e. it's not huge, but it's not small, either. It does have the one-way valve to hold the gas in, but it's got a big opening that funnels the gas through that one-way valve. If I'm shallow, one good exhaled breath will generally get it to the surface, no problem, but it probably won't fill it and make it stand tall at the surface. I'm okay with that. If I'm already shallow when I send it up, I'll be there with it soon enough and can fully inflate it then, if needed. If I'm at depth, one good breath will probably get it reasonably full at the surface. Either way, using 2 breaths to fill it more before releasing it is generally not a problem, either.

I was taught to do it this way by my original tech instructor. I think he said he does it that way so as not to waste gas. That seems like a very minor benefit, to me.

I have also practiced it before where I switched to my backup reg on a bungee necklace and then used my primary (which is on a longer hose), holding the 2nd stage under the opening and purging the reg to put gas in the bag. That is very easy, but it has the downside that if you are in very cold water purging your 2nd stage has the potential to start a freeflow. And because it has the potential, I prefer not to do it that way at all. I don't want to do it one way most of the time but a different way when I'm in cold water.

Catching exhaust bubbles has no potential to start a feeflow (practically speaking). It's also pretty easy once you practice a bit and get the hang of where to position the bag. You do want to do it by tilting your head to the right, so you are catching bubbles that are coming out of the left side of the reg. Less chance of the bag/reel getting tangled up with a reg hose, I think.

I don't like any method that involves having my reg out of my mouth while inflating the bag. I feel like there is too much opportunity for an "oh, shoot" moment when filling the bag. Adding "I don't have a reg in" to that "oh, shoot" moment does not seem wise, to me. It's not about what happens when you do everything correctly. It's about what happens when you make a mistake - or when some weird unforeseen thing happens that puts you out of whack. What? A weird random current caused the bag to wrap itself around you from behind while you were trying to blow some air in?? And it started to pull you up while at the same time you don't have a reg in your mouth?? Anyway, I'm just saying. I don't like doing "stuff" while I don't have a working reg in my mouth.

I also don't like the idea of using a low pressure inflator hose to fill the SMB. Where does it come from? Am I disconnecting my LPI from my BCD to briefly jam the SMB inflator into it? Disconnecting and reconnecting the inflator is usually a 2-handed operation (for me, anyway). I don't like that. I also don't like taking an important part of my gear apart while underwater, unless I have to. Which means if there is another, easy, way to accomplish the task, I prefer that. Am I adding a second BCD inflator hose to my 1st stage, just so it's there to use to inflate my SMB? I like that better than disconnecting from my BCD. But I still don't like it. It's extra "stuff" that I really don't need. One more thing to catch on stuff and/or break.

I think it's good to practice more than one way - for a variety of reasons. But, for normal deployment, filling using exhaled gas may take a little more practice, but I think it's easiest and safest, once you've gotten the hang of it.

 

[boulderjohn]

I also don't like the idea of using a low pressure inflator hose to fill the SMB. Where does it come from? Am I disconnecting my LPI from my BCD to briefly jam the SMB inflator into it? Disconnecting and reconnecting the inflator is usually a 2-handed operation (for me, anyway).

A lot of people who do that are using a deco or pony bottle with an extra LP hose on it.

 

[Lorenzoid]

I think Stuart summed it up well. But have there actually been many instances of someone using the inflation tube getting into trouble who would not have gotten into trouble had he used the reg exhaust method? Is this one of those things that sounds like it reduces a risk, but in reality the risk is small enough to be outweighed by the advantages of the alternative method?