How to handle both DSMB and loop volume while bailing out ?

***ScubaDadMiami*** · 24th March 2006, 19:00

Is it possible that you need to add a small amount of weight? I realize that you want to be neutral. However, don't forget to account for things like tanks (and bailouts) being near empty at the end of the dive (as opposed to being perfectly weighted with plenty of gas aboard and full tanks). If you are that close to the edge from blowing up to the surface when you , even a slight change to positive from the counterlungs could be keeping you from holding your stops.

I just did this ascent (on open circuit) several times over the course of my training (including with a bailout bottle that was mostly empty). I left the OPV open, and I would try to depress it and/or squeeze out the gas when possible during the ascent. I was able to do this while also venting from the wing and the drysuit.

Maybe my counterlungs don't hold the volume that yours do. So, I don't get that big of a shift to positive from their inflation as I ascend. This is why I am just wondering about the weighting issue as a factor.

Is this an idea worth thinking about?

***Decodiver*** · 24th March 2006, 22:39

I agree with ScubaDad here. If you are becoming strongly positive, with an empty wing and tight drysuit, upon CL inflation, then you probably need more weight.

Cheers,

Dave Cooper.

Nick uk. · 24th March 2006, 22:53

Once you pass to OC, couldn't you deflate the lungs before making the accent....

silent running · 25th March 2006, 03:42

Quote: (Originally Posted by Drmike)

if no opv is fitted (fit one) or you will have to control cl volume by going back top the loop and sucking/blowing on way up....dont forget to turn off your unit!

Hello Francois, I agree with this. First of all, turn off the unit or if ECCR turn off the O2 valve. Then empty the wing and either the CLs or the drysuit-not sure which is better as I am a warm water diver. But obviously an OPV on both is very important.
On the CLs it should be high enough on the unit to vent and do you some good in an emergency ascent. It should be adjustable-crank it all the way loose in this event so that it will vent by itself at the slightest positive pressure, or with a simple push on the lung or valve. With this situation, you shouldn't have any more trouble deploying your SMB than if you were controlling the wing dump. In fact on my unit, the Prism, this is probably easier than holding up the inflator and venting. I just need to reach up with my right hand and tap the OPV/lung.
I used to wonder whether OPVs were really necerssary, but after practicing OC bailout drills and spending time decoing at 20ft in 8ft seas, I think it's definitely required if only for the deco and bouancy control factor alone. Not to mention the embolism factor... -Andy

Francois · 30th August 2006, 09:01

Sorry, I did'nt connect me the last four monthes.

Thanks a lot to everybody for the answers.

In fact, I put a 3Kg belt, and tried with my CCR tanks and my 2 BO tanks nearly empties. Now, it's OK, and it's much easyer to manage an OC BO ascent, while reeling the DSMB.

But now, I need to feed the wing with another tank, as gas use for the wing has becomed a bit heavy, and I don't want to waste He mix for the wing.

For the moment, I have connected the wing to the dry suit tank, keeping a hose on the diluent tank in case of failure of 1st stage suit tank.

Do you use two tanks for wing and suit, or just one tank for both suit and wing and redundant hose on diluent to connect the wing in case of suit tank failure ? (as I do now).

Thanks.

24th March 2006, 19:00	#11 (permalink)
*ScubaDadMiami* Moderator Current Rebreather/s: Optima Other Rebreather/s: Join Date: Sep 2005 Location: Florida, USA Posts: 2,141	Re: How to handle both DSMB and loop volume while bailing out ? Is it possible that you need to add a small amount of weight? I realize that you want to be neutral. However, don't forget to account for things like tanks (and bailouts) being near empty at the end of the dive (as opposed to being perfectly weighted with plenty of gas aboard and full tanks). If you are that close to the edge from blowing up to the surface when you , even a slight change to positive from the counterlungs could be keeping you from holding your stops. I just did this ascent (on open circuit) several times over the course of my training (including with a bailout bottle that was mostly empty). I left the OPV open, and I would try to depress it and/or squeeze out the gas when possible during the ascent. I was able to do this while also venting from the wing and the drysuit. Maybe my counterlungs don't hold the volume that yours do. So, I don't get that big of a shift to positive from their inflation as I ascend. This is why I am just wondering about the weighting issue as a factor. Is this an idea worth thinking about? __________________ Howard Packer IANTD CCR Instructor Miami Beach, Florida CCRDiveTraining.com
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24th March 2006, 22:39	#12 (permalink)
*Decodiver* Administrator Current Rebreather/s: Other CCR Other Rebreather/s: Other CCR Join Date: Jan 2005 Location: Geneva Posts: 2,197	Re: How to handle both DSMB and loop volume while bailing out ? I agree with ScubaDad here. If you are becoming strongly positive, with an empty wing and tight drysuit, upon CL inflation, then you probably need more weight. Cheers, Dave Cooper. __________________ CCR/OC Trimix Instructor Trainer CCR Training to Mixed Gas in Switzerland, France, UK & Germany on Megalodon/COPIS-Megalodon/KISS/Sport KISS/Ouroboros/rEvo/Inspiration/Evolution/Sentinel www.zerogravitydiving.com Rebreather World Terms & Conditions Last edited by Decodiver : 24th March 2006 at 22:44.
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24th March 2006, 22:53	#13 (permalink)
Nick uk. Made in England. Current Rebreather/s: Inspiration Classic Azimuth Other Rebreather/s: Azimuth Join Date: Nov 2005 Location: Viale C.Colombo 75 Marina di Carrara. MS 54036 Italy Posts: 579	Re: How to handle both DSMB and loop volume while bailing out ? Once you pass to OC, couldn't you deflate the lungs before making the accent.... __________________ If it aint broke....don't fix it, and if it is.............well......get another one! divechief2000@hotmail.com
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25th March 2006, 03:42	#14 (permalink)
silent running Mature mouth breather Current Rebreather/s: Prism Topaz Other Rebreather/s: Join Date: Jun 2005 Location: U.S.A. Brooklyn, New York Posts: 1,836	Re: How to handle both DSMB and loop volume while bailing out ? Quote: (Originally Posted by Drmike) if no opv is fitted (fit one) or you will have to control cl volume by going back top the loop and sucking/blowing on way up....dont forget to turn off your unit! Hello Francois, I agree with this. First of all, turn off the unit or if ECCR turn off the O2 valve. Then empty the wing and either the CLs or the drysuit-not sure which is better as I am a warm water diver. But obviously an OPV on both is very important. On the CLs it should be high enough on the unit to vent and do you some good in an emergency ascent. It should be adjustable-crank it all the way loose in this event so that it will vent by itself at the slightest positive pressure, or with a simple push on the lung or valve. With this situation, you shouldn't have any more trouble deploying your SMB than if you were controlling the wing dump. In fact on my unit, the Prism, this is probably easier than holding up the inflator and venting. I just need to reach up with my right hand and tap the OPV/lung. I used to wonder whether OPVs were really necerssary, but after practicing OC bailout drills and spending time decoing at 20ft in 8ft seas, I think it's definitely required if only for the deco and bouancy control factor alone. Not to mention the embolism factor... -Andy Last edited by silent running : 25th March 2006 at 03:47.
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30th August 2006, 09:01	#15 (permalink)
Francois New Member Current Rebreather/s: rEvo Other Rebreather/s: rEvo Join Date: Dec 2005 Location: Girona, Spain Posts: 11	Re: How to handle both DSMB and loop volume while bailing out ? Sorry, I did'nt connect me the last four monthes. Thanks a lot to everybody for the answers. In fact, I put a 3Kg belt, and tried with my CCR tanks and my 2 BO tanks nearly empties. Now, it's OK, and it's much easyer to manage an OC BO ascent, while reeling the DSMB. But now, I need to feed the wing with another tank, as gas use for the wing has becomed a bit heavy, and I don't want to waste He mix for the wing. For the moment, I have connected the wing to the dry suit tank, keeping a hose on the diluent tank in case of failure of 1st stage suit tank. Do you use two tanks for wing and suit, or just one tank for both suit and wing and redundant hose on diluent to connect the wing in case of suit tank failure ? (as I do now). Thanks. __________________ François "If redundancy is not your epigraph, stupidity might be your epitaph" (Gary Gentile)
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