Possible to remain completely neutral when deploying SMB?

[illFisch]

My guess is that you aren't in fact neutrally buoyant when you start to play with the SMB. The difference is that normally you will vent the gas from your lungs before you start to drift up and this will correct the added buoyancy of your full lungs (keep in mind your neutral buoyancy is the average of your breathing and you change this when you don't include the low volume part of the cycle).

Concentrating on the SMB also may mean you pay less attention to your position in the water column and by the time you've finished with the SMB you may have moved up enough that the volume change is accelerating your buoyancy change.

 

[Dive-aholic]

I teach my students to get slightly negative prior to deploying an SMB. Get the SMB out and prepared to shoot while neutral. Right before inflation dump some air from the BC, then fill your SMB using your preferred method. I caution anyone shooting an SMB in colder waters to not use the regulator method because you are risking a free flow. Once you deploy the SMB and it starts ascending, get neutral again. The pull of the SMB on the line will counteract the slightly negative buoyancy you establish just before deployment.

 

[tracydr]

I use my flippers to swim head down just a tad while I fill it up. When I let it go, I make my flippers stop and then I'm neutral again.

Also helps to fill it up deeper so you don't have to put as much air in the bag to fill it because it expands.

Flippers?

 

[Michael Guerrero]

Flippers?

I know they have a status on here of "I'm a Fish". Is there one for "I'm a Walrus"?

 

[FinnMom]

I get just a tiny bit negative before deploying and then fin just a tiny bit to stay level.
Next I add a little bit of air to get the bag to open up and take shape but so little that it isn't pulling much at all (maybe just enough that together we are again neutral).
Last of all I take one deep breath and exhaust it into the bag, immediately letting it go.

As others have said they do, I also have the double ender hanging on the line and I hold the double ender in my left hand when the bag takes off. I let the spool spin freely above my rt hand. I could hold the spool if I had bare hands or thinner gloves, but with clumsy drygloves I let it spin above my hand because the glove fingers get caught so easily.

 

[Jim Lapenta]

I have tried all of the above methods and they all work. But when I did my Sidemount class with doppler one of the things we had to do was deploy an smb while remaining neutral and in trim. It does not specify a size for the buoy in the standards. So I took my little HOG 36 inch smb with Manta nano reel and had it rigged, deployed, and shot while others in the class were still unrolling their six foot tubes and getting them out of their way so they could see to deploy them. on what for me was a 1/4 - 1/3 of a breath. About what it takes to clear a fully flooded mask. so any change in buoyancy was negligible. Another instructor observing the class found it quite amusing as I was hanging there waiting for the other guys. It seriously took less than 30 seconds. And I used a reel for the same reason as finmom has with gloves and spools. But that will be a thing of the past with the new spools that were at dema that I'll.have in soon. The center is solid and the spool.spins around it. But the center is also removable for those who want a traditional spool.
Sent from my DROID X2 using Tapatalk 2

 

[Searcaigh]

I usually go slightly negative and exhale into the SMB, however I like the dumping from BC/Wing idea, must try that out next weekend.

 

[Agility]

If you use a large (read long) SMB at shallow depth the fact that the air in the SMB has already expanded on its way up in the sausage will be enough to offset your buoyancy if you were strictly neutral at the beginning of the exercise and have not let go of the buoy yet.

 

[DivemasterDennis]

Your method sounds fine. You are replacing the SMB air with more air, but hey, they is no gauge to measure that. I always have a buddy hold on to me during smb deployment to assist in maintaing neutral buoyancy, and recommend the same.
Divemaster Dennis

 

[g1138]

When you breath into your SMB your trim and center of gravity are often shifted so your head goes up slightly.
The air in your SMB rises to the top (2m) and expands, causing you to in fact not be neutrally buoyant. If you're not finning or shifting body weight to correct towards a head down position, you'll not be compensating for this.
Imagine if you're neutrally buoyant at 5m, and rise to 3 meters, your air expands and you're not neutral.