redundant buoyancy with a wet suit.

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Originally Posted by stairman

Ive never tried riding out a lift bag, sounds like fun.

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I've never ridden one out of a cave but....

We had to do something similar for the Normoxic and Trimix classes. This was a pool exercise only so no dry suits, only shorties more for padding than anything else. The idea was to completely vent all gas from wing, obviously to simulate total loss of buoyancy from both wing AND drysuit. We all had with steel doubles and two deco bottles (1 AL80 & 1 LP46).

The idea was to deploy the bag at the bottom of the pool (ok it was only 12ft of water) BUT get to the surface and stay at surface with head out of the water for...I don't remember how long 5 to 10 mins????

Try it sometime, it's damn near impossible LOL and that was only for a couple min's.

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Originally Posted by Line Squirrel

I've never ridden one out of a cave but....

We had to do something similar for the Normoxic and Trimix classes. This was a pool exercise only so no dry suits, only shorties more for padding than anything else. The idea was to completely vent all gas from wing, obviously to simulate total loss of buoyancy from both wing AND drysuit. We all had with steel doubles and two deco bottles (1 AL80 & 1 LP46).

The idea was to deploy the bag at the bottom of the pool (ok it was only 12ft of water) BUT get to the surface and stay at surface with head out of the water for...I don't remember how long 5 to 10 mins????

Try it sometime, it's damn near impossible LOL and that was only for a couple min's.

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Thus you proved it feasible for use in a cave environment.... Since as soon as one gets to the surface outside of a cave, one can simply get out of the water and put the gear on shore. :)

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Originally Posted by Tegg

Thus you proved it feasible for use in a cave environment.... Since as soon as one gets to the surface outside of a cave, one can simply get out of the water and put the gear on shore. :)

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DOH! Now why didn't I think of that?

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Originally Posted by Line Squirrel

I've never ridden one out of a cave but....

We had to do something similar for the Normoxic and Trimix classes. This was a pool exercise only so no dry suits, only shorties more for padding than anything else. The idea was to completely vent all gas from wing, obviously to simulate total loss of buoyancy from both wing AND drysuit. We all had with steel doubles and two deco bottles (1 AL80 & 1 LP46).

The idea was to deploy the bag at the bottom of the pool (ok it was only 12ft of water) BUT get to the surface and stay at surface with head out of the water for...I don't remember how long 5 to 10 mins????

Try it sometime, it's damn near impossible LOL and that was only for a couple min's.

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On the surface, if you need to be there long term, you always have the option of dropping equipment or hanging the tanks under the bag and slipping out of the harness. You just need to do what works and think outside the box a little.

During the ascent, it depends on the bag and the technique. In OW where you can ascend more or less vertically any open or semi closed cuircuit bag can work as long as it has a dump valve you can easily reach. I have found it helps to secure it to the scooter D-ring so that it rides even with your chest. You can then add gas to the bag with the long hose reg and adjust buoyancy as needed on the way up. It does take practice, but with practice it is do-able. ONce you establish an upline, you can then keep things a pound or two negative and it gets even easier to do a longer deco.

If you use a closed circuit bag, then you can use the inflator hose to fill the bag, stay horizontal and keep the bag under your chest. That could even work in a cave exit, although it would be a major challenge, especially in flow and/or saw tooth profiles and/or restrictions.

My preference in deep OW trimix dives if using a wet suit is to just stack a wing. I use an old rec wing and the bungee keeps it in tight along the tanks. The corrogated inflator hose runs along side the other one and is connected but the hoses are shorter, so you can still access it in an emergency but won't access it by mistake. I'd do the same if diving wet in a cave, but that is not normally the case, and I am normally sidemount in a cave, so stacking a wing would pose some additional issues.

I'd also not be opposed to using a dual bladder wing, I just don't own one and don't see enough advantage to go out and buy one.

Having just finished AN/DP in Florida in a wetsuit, I'm looking forward to trying this. It appears that if I clip my Halcyon closed-circuit bag to my scooter D-ring, the valve will be right in front of my mouth so I can orally inflate it. The dump valve is on top within easy reach too. I'm not sure how swimming it horizontally will work out, though.

You can orally inflate, but it works better to use the inflator hose. For swimming horizontally, the smaller version of the Halcyon bag works better than the larger one.

I had a buddy who was diving wet with a single air cell and a tear formed in the air cell during the dive right where the curragated hose connects. He started sinking deeper into the system he was in until his buddy quickily shot down and took hold of him and used his BC to get the both of them out. I learned from his incident and I have a dual bladder NOMAD since I still dive wet.

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Originally Posted by Slüdge

After reading the IRAP in question, if I dived wet I'd definitely use a dual-bladder wing, but in the meantime (until I got one), I'd carry a lift bag or SMB for emergencies.

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Hopefully, I will be diving JB on Monday - in a dry suit :) I have never used a lift bag in a cave for buoyancy but i may take one and try it on my exit between the 1st and 2nd breakdown. I'll let you know how it goes.

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Originally Posted by DA Aquamaster

For swimming horizontally, the smaller version of the Halcyon bag works better than the larger one.

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That's the one I have. I like it--it's quick to put up with a drysuit hose, and I think there's less chance of entanglement when doing so.

"Hopefully, I will be diving JB on Monday - in a dry suit I have never used a lift bag in a cave for buoyancy but i may take one and try it on my exit between the 1st and 2nd breakdown. I'll let you know how it goes."

Just woundering why anyone would ever "try" this in a cave. Why not in the open water?