Deploying SMB

[hobodiver]

If you fill it half up at any decent depth, it'll be FULL when it hits the surface. Boyles law and all that.

Yes, I understand that. My point was that if I am neutrally buoyant and then inflate an SMB until it's half full, I will have + 12lb buoyancy until I release it.

 

[irishsquid]

For enjoyment only.
ªèn Lift Bag Deployment
An article from Jim Driggers

I recently had my first experience deploying a lift bag...Was my first try like this? No. I wish it went as smoothly.

Nice! That WAS enjoyable.

 

[bygolly]

Yes, I understand that. My point was that if I am neutrally buoyant and then inflate an SMB until it's half full, I will have + 12lb buoyancy until I release it.

Depends on how you inflate it. If you use your reg or your LP hose, yes you will end up quite positive. If you orally inflate with one breath nothing changes until you take the next breath. If one breath inflates it enough just let it go as you replace the reg and take your next breath. If you inflate with air from the BC nothing changes again but you will have to quickly re-inflate the BC when you shoot it. I haven't tried inflating the SMB with the air from my BC yet as it sounds tricky and I have only had it described to me but it is something I would like to try.

 

[rjack321]

Does anyone else see something wrong with this?

"Lastly, SMBs should provide enough lift such that divers cannot easily pull it back down to depth. Generally 25 lbs or more of lift is plenty."

"8.) Holding the SMB and spool with the left hand, inflate the SMB till about half full."

Inflating an SMB w/25lbs of lift until it's half full will cause one to have 12 lbs of +ve buoyancy.

First of all, don't hang on SMBs. That negates that need for massives sizes regardless of application. Pick one that is big enough for the dive (which may be a nice compact 3ft tall one that has 6lbs of total lift or it might be 60lbs and 6ft tall). 2nd, shoot the bigger ones from deeper depths. If you're at a shallow site but need lots of SMB visibility (offshore) you'll have to finish inflating it on the surface.

 

[sschlesi]

Watching the two videos posted above, I notice that both divers kept their spools separate from their SMB, and connected them before deploying them. Why wouldn't they have them already connected, removing the need to connect them underwater?

 

[ppo2_diver]

Mostly personal preference. I keep mine attached.

 

[Blackwood]

Why wouldn't they have them already connected, removing the need to connect them underwater?

Maybe they only have one spool but multiple uses. Example: running a search pattern and later shooting a bag (note that's not necessarily the best plan, as you may have need to shoot the bag immediately after finding whatever you've been searching for).

 

[Jan Kruger]

So now i also know how to deploy this thing that i have been carrying with me for a while....

 

[Puffer Fish]

Yes, I understand that. My point was that if I am neutrally buoyant and then inflate an SMB until it's half full, I will have + 12lb buoyancy until I release it.

There is a bit of a timing trick to that.. my smb has over 50 lbs of lift.. so half full is a lot.

Even if you use your octo to fill the bag (I do about half the time).. exhale, and wait till you start to drop... then fill quickly.. I usually count for two counts... and release.

If you do it right... you drop a bit, then the pull of the bag starts to pull you up and you release it... then take a breath.

Done right, you end up in the same spot.

And I keep mine smb in a mesh pouch attached to the bottom of my plate.. and my reel on my side.... not connected.

 

[rongoodman]

Watching the two videos posted above, I notice that both divers kept their spools separate from their SMB, and connected them before deploying them. Why wouldn't they have them already connected, removing the need to connect them underwater?

If they're practicing or demonstrating for GUE Fundies, it's done that way just to provide a little extra task loading. I carry my already attached on a regular dive, but know that I have to be able to do it from scratch for the class.