New rEvo BOV
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Brad_Horn
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This is a quite common design issue with certain BOVs. The risk is descending with feed gas isolated either at the valve or with a shutoff accidentally engaged. You then swap to OC in an emergency and get a mouth full of water.
An engineered solution for BOVs which has been around for a while, that solves this is a 3D lip seal, that lets gas flow through under vacuum from the CC to the OC side. Means that the diaphragm won’t collapse on descent. See page 60 http://www.deeplife.co.uk/or_files/FMECA_OR_V4_180821.pdf
They have actually been quite open with you, in that very likely the WOB in OC mode is very close to 3.0J/L at 50m on air at 62.5lpm. Which is why they don’t want to give you the specifics. They certainly aren’t the first manufacturer to do so.
You could possibly have a guess at what the CC WOB of the BOV might be, by comparing its dimensions with the data that DL list on page 63 http://www.deeplife.co.uk/or_files/FMECA_OR_V4_180821.pdf
If you had wanted a low WOB BOV there is only one right to left gas flow solution for the rEvo.
http://www.deeplife.co.uk/or_files/DV_DL_ALVBOV_Breathing_Params_A3_100318.pdf
https://www.opensafety.eu/datasheets/ALVBOV_40m_75lpm_air_081014.pdf
It just doesn’t come with any branding, but ships with gagstrap, breathing hoses and user manual included. Any specific loop adapters required for rEvo’s are available from tecme.de Open Safety Equipment Ltd
That said it is good to see rEvo slowly improving the performance and safety of their unit with a BOV. Even if they haven’t fully tested it yet.
AFAIK that narrows the BOV choice down to 1.
However it is CE certified for use to 100m and OSEL rate it for use to 350m. At that depth with a breathable gas it still passes the EN250 WOB requirement!
At this point the industry really has only ‘just’ got to the point of considering a BOV as safer than a DSV. They haven’t yet switched onto needing to seperate the various BOV options by actual documented tested performance. In the most part they can’t do this simple activity as the OP has proved, except in the most coarse sense, in that at best it may scrape through the CE requirements. There is still a wide gulf from the CE limits to the optimal equipment performance.
BMCL units don’t have to breathe poorly. You just need to invest in some professional R&D&Testing. DL designed units WOB are quite reasonable even at 350m at 90RMV both horizontal and vertical http://www.deeplife.co.uk/or_files/DV_OR_WOB_Respiratory_C1_101111.pdf
In theory the rEvo will still retain its CE certification with the BOV as it cumulatively should be better, being theoretically a lower WOB component. But the only thing that will confirm this is testing with the results verified by their Notified Body and until that is done the rEvo wouldn’t appear to retain its CE with the BOV fitted. But I’m sure others inclusive the various instructors on the unit are more informed about this and have already considered it.
Obviously if rEvo do what DL have done and publish testing proving that the CC WOB of the BOV is lower than the DSV, then this is just a paperwork issue for their Notified Bodies technical file in order to get their certification updated.
OSEL can sell the ALVBOV as an upgrade for any CE certified rebreather as no other stock DSV/BOV been identified as having lower WOB…. or safer.
Its like listening to an answering machine. Same lines spun out every time.
silent running
Contributor
Hi Brad, I know you say this, but the WOB of the Apocalypse is achieved with a cartridge scrubber, which however well implemented in the design, still carries with it the risk of CO2 bypass at high RMV. If you care to explain exactly how your cartridge scrubber design avoids this remarkably bad feature, as opposed to the Optima or Poseidon, please do, though perhaps in a different thread so as not to clutter this one?
OP
My first dive on Sat was with the gag strap. I do think it is most comfortable in the water with the gag strap. But, I got a lot of water in the loop with that mouthpiece/gag strap. I switched to a different mouthpiece (thus, losing the gag strap) for dives 2 and 3 and got almost no water in.
My mouthpiece/gag strap is 8 or 10 years old. I'm not sure if it letting water in because it's old, or if it's just letting me relax my mouth more because I don't have to do any work at all to keep the BOV in my mouth, and my more-relaxed mouth is letting more water in.
I'm debating to get a new mouthpiece/gag strap and try that. It just sucks because they are something like $120.
JonG1
Contributor
First a few caveats and an apology for the OT comments but....
So I am relatively new to CCR (2 years in December), not diving hypoxic dil, not covering 1000's of metres in the OHE maybe 300 or so at the moment.
With those out of the way, I wanted to ask whether there is an issue or consideration in terms of the additional failure points and decision trees (potentially inaccurate connection) associated with QD's of whatever design.
How often is it necessary to connect a different dil source to a unit? In a cave I can see that being possible with a saw tooth profile or in the need of SCR maybe, but even an 80 at 3x the volume on SCR could go a long way, and if you have taken a CO2 hit and depleted the bailout, its likely the RB is in no fit state to go back onto for SCR anyway so swapping new bottles to it is not a necessity?
If the initial bailout bottle is big enough (huge variable) even in the event of a CO2 incident to allow a modicum of control to return, standard 2nd stages on additional bailout can be used without any further connections required.
In OW if I was low or out of dil I'd be on the ascent or probably at steady depth to the shot so unlikely to need it or could add bailout via my BOV.
Not trying to start a ruck just genuinely interested and am on the verge of installing a QD for my deep bailout but have been dithering on the decision to press the button.
When I started out I took the view that less was more, (KISS Classic) so removed the manifold and the swivel elbows, dil is on board and 3l also feeds wing. My BOV and necklaced 2nd stage hose are zip tied into the unit and their first stage sits under my arm, clipped off until the bailout goes on, either on the bench in the back of the boat or next to the head pool.
Certain caves next year may require the ability to remove the bailout or don it in the water (Landenouse) hence my interest, plus one of the boats may not have a lift that we are diving from.
I just worry that with more to go wrong on the RB and stages, especially infrequent use items, I might create a problem that was solving an issue that didn't exist.
So I am relatively new to CCR (2 years in December), not diving hypoxic dil, not covering 1000's of metres in the OHE maybe 300 or so at the moment.
With those out of the way, I wanted to ask whether there is an issue or consideration in terms of the additional failure points and decision trees (potentially inaccurate connection) associated with QD's of whatever design.
How often is it necessary to connect a different dil source to a unit? In a cave I can see that being possible with a saw tooth profile or in the need of SCR maybe, but even an 80 at 3x the volume on SCR could go a long way, and if you have taken a CO2 hit and depleted the bailout, its likely the RB is in no fit state to go back onto for SCR anyway so swapping new bottles to it is not a necessity?
If the initial bailout bottle is big enough (huge variable) even in the event of a CO2 incident to allow a modicum of control to return, standard 2nd stages on additional bailout can be used without any further connections required.
In OW if I was low or out of dil I'd be on the ascent or probably at steady depth to the shot so unlikely to need it or could add bailout via my BOV.
Not trying to start a ruck just genuinely interested and am on the verge of installing a QD for my deep bailout but have been dithering on the decision to press the button.
When I started out I took the view that less was more, (KISS Classic) so removed the manifold and the swivel elbows, dil is on board and 3l also feeds wing. My BOV and necklaced 2nd stage hose are zip tied into the unit and their first stage sits under my arm, clipped off until the bailout goes on, either on the bench in the back of the boat or next to the head pool.
Certain caves next year may require the ability to remove the bailout or don it in the water (Landenouse) hence my interest, plus one of the boats may not have a lift that we are diving from.
I just worry that with more to go wrong on the RB and stages, especially infrequent use items, I might create a problem that was solving an issue that didn't exist.
silent running
Contributor
I have an ALVBOV, and am impressed with the design and workmanship, and of course the specifications, which is why I bought it.
However wordy Brad may be sometimes, either what he says is true or not. I was not aware of the vacuum problem with the diaphragm seal and wonder now how many other BOVs have this same problem as the rEVO/Mares does. It’s a very bad feature and could seriously hurt someone or at least delay you from diving if discovered beforehand.
This then begs the question, does everyone test the OC side of their BOV during predive? Does the BOV OC diaphragm on BOVs that do not have the right lip type seal, collapse every time you pull a negative test, or only if it is a very hard suck negative test?
As a CCR newb with just over 30hrs, I test my Skrimp pre-dive, in the water. I have also done a suck test and have never collapsed the diaphragm.
Hey *****canoe, you should test the rEvo BOV. Throw it in a plastic bag with an iPhone, that should be good enough for your next pdf.
uwxplorer
Contributor
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