DSMB Technique

[Dan G]

Inflating a 6' DSMB at 15' is not easy. Plenty of good suggestions here. I have always used the valve and exhaled into the sausage. A technique I plan to try on my next trip is to fill the DSMB via the exhaust of the reg in my mouth. I wear my back up on a necklace around my neck, so I do not see myself using that to fill it.

 

[Gelirfella]

it’s really better to find a 30 foot depth or whatever you want to use and do it for 45 minutes or an hour ….until you get it right.

Lots of good suggestions. I use a long hose with a necklace so will work on oral inflation. LP inflator isn’t a terrible idea but seems like I should get down oral inflation first and not crazy about disconnecting my BC just yet. I think this idea is a good one. Might be hard to find a buddy willing to hang out and just work on their own skills while I do this. Do people usually do this kind of thing solo? Strikes me that by the time you have the skill set to reliably solo dive and do something like this you’ve probably got basic skill sets like this down already. Or is it generally felt that sitting at a 30 foot hard bottom in a quarry is so low risk that the principles of redundancy etc that apply to solo diving aren’t applicable?

 

[Dan G]

Lots of good suggestions. I use a long hose with a necklace so will work on oral inflation. LP inflator isn’t a terrible idea but seems like I should get down oral inflation first and not crazy about disconnecting my BC just yet. I think this idea is a good one. Might be hard to find a buddy willing to hang out and just work on their own skills while I do this. Do people usually do this kind of thing solo? Strikes me that by the time you have the skill set to reliably solo dive and do something like this you’ve probably got basic skill sets like this down already. Or is it generally felt that sitting at a 30 foot hard bottom in a quarry is so low risk that the principles of redundancy etc that apply to solo diving aren’t applicable?

If you can find a buddy who wants to work on DSMB deployment or other skills that would be ideal. You can get wrapped up in the DSMB line or have something happen where having a buddy around is nice.

When using an inflator, people have a second inflator hose attached to their first stage. They do not remove the inflator hose attached to their wing/BC and then replace. I would be interested to hear from others if they have ever had an issue or witnessed an issue with someone getting their inflator hose stuck on the DSMB valve or faced any other issues with this technique. I must admit I am hesitant to attach myself to a DSMB.

 

[Sensorone]

You might start with a DSMB of 44 to 48 inches. I prefer the close bottom type with an OP valve. I can usually get enough air in it with one breath from 20 feet. I also use a Y fitting sometimes to inflate from my BC LP hose, especially the jumbo DSMBs:





The DSMB should have a non-locking inflator:



I stick it in the fitting, psssst, zoom, up, up and away.

Unfortunately, I have not seen those fittings in years though there are some that are reverse of it that would likely work as well or better.

Available from Pirhana.works like charm. I remove the retention balls inside the barrel of the angled fitting so I don't have to retract the collar- just shove the inflator stem of the DSMB into it and away it goes.

 

[Edward3c]

If you can find a buddy who wants to work on DSMB deployment or other skills that would be ideal. You can get wrapped up in the DSMB line or have something happen where having a buddy around is nice.

When using an inflator, people have a second inflator hose attached to their first stage. They do not remove the inflator hose attached to their wing/BC and then replace. I would be interested to hear from others if they have ever had an issue or witnessed an issue with someone getting their inflator hose stuck on the DSMB valve or faced any other issues with this technique. I must admit I am hesitant to attach myself to a DSMB.

I use my drysuit or bc inflator, whichever I fancy. When I first fitted the attachment I made the mistake of placing it horizontal so the sideways pull nearly locked it on. Now it’s virtual the hose just slides off when the blob goes up. Been using it for over 6 years.

There is no locking indent on the filling nipple like the drysuit/bc one.

 

[Sensorone]

I use my drysuit or bc inflator, whichever I fancy. When I first fitted the attachment I made the mistake of placing it horizontal so the sideways pull nearly locked it on. Now it’s virtual the hose just slides off when the blob goes up. Been using it for over 6 years.

There is no locking indent on the filling nipple like the drysuit/bc one.

No locking indent on the DSMB inflation stem is correct, but the fitting in the picture has locking small ball bearings inside the sliding collar that once removed no longer impede the insertion of the stem, the locking indent is on the bottom of the stem not the end being inserted. Not having to retract the collar saves a step in the inflation process.

 

[b1gcountry]

I've never found it important to fully inflate a 6' smb at depth. Get whatever air you can in one or two breaths then let it go. You need to keep downward pressure on it either way to keep it upright.

I really dont like the idea of using a power inflator at depth. For one thing you simply dont need it. Getting the SMB to the surface gives the boat an idea of where you are at deco. You should deploy as soon as you get swept off the anchor line, and boat folks should be watching down current. They will see an smb unless they're asleep. If you need it for dive regulations, then you should fly it from the start.

Extra power inflators are just gear looking for problems to solve.

 

[Kendall Raine]

I use a closed cell bag which I inflate using a dry suit hose (36”) whether I’m diving wet or dry. If wet, the hose tucks in my waist strap and is only used to shoot a bag. This also works with an open bottom or duck bill SMB by attaching a rubber inflator nozzle (aka doggie dick).

The long length of hose allows you to keep the bag, spool and LPI at arms length out front and away from the body thereby significantly reducing the risk of entanglement leading to uncontrolled rapid ascent. Using an LPI allows the bag to fill quickly avoiding buoyancy creep during oral inflation.

The Y connector mentioned previously strikes me as a really accident prone idea because the whole assembly-SMB, spool and LPI, is in close to the body (particularly if using a shorter corrugated BC inflation hose) where it’s harder to see and easier for stuff to get caught up. Same problem with using a second stage unless it’s on a long hose. Oral inflation is just too slow, involves buoyancy creep if shallow, and also requires getting the bag and spool in close to the body.

 

[Nemrod]

Each to their own. The Y fitting has worked fine for me for years and it is transparent to my dive when not in use. I am not an underwater dive shop Christmas tree so there is nothing on me to hang up and having an extra LP hose is just another hose I do not need along with the assorted gizmos and have not used a dry suit in years. Some of my regs have a Y fitting, some do not, if not I just orally inflate. If the Y fitting is pointed reverse of my picture it is even less likely to hang up as the nipple shoots out of the LP fitting with some force and is gone in a wink.

Getting blown off a wreak or anchor line is not the only reason to send up a dsmb. In Cozumel or Florida drift diving, or even the Red Sea diving, if away from the main group (or guide/DM), sending up a dsmb on the safety stop is a common practice. Send it up earlier if you want when beginning ascent, sometimes that is easier because one breath at depth will fill the bag and there is less buoyancy change should you need two breaths. A lot of dives (again Cozumel as an example) may have started out on the wall in 100 feet of water looking into the bottomless blue but end up near an hour and a half later in 15 or 20 feet of water. You are not going to swim back to the wall and descend to 60 feet to inflate your dsmb, you will just shoot it from your final depth. Every circumstance is different and needs some flexibility to the occasion.

 

[inquis]

For all those commenting they use their drysuit or BC inflator hose, do you flush said inflator after a saltwater dive? (I'm assuming you reconnect after deployment.)