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Thread: Review: *New* Poseidon Back Mounted Counterlungs

  1. #1
    J missionmtb is an unknown quantity at this point missionmtb's Avatar
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    Feb 2015
    United States


    Review: *New* Poseidon Back Mounted Counterlungs

    Hi All,

    I've been interested in BMCLs for my Se7en for a while despite mixed reviews about their WOB. Unfortunately, up until recently the only options were to either turn the stock OTSCLs backwards or use adapters for other brands of CLs. The first option seemed awkward and the second typically runs in the neighborhood of $1000 USD after all is said and done...

    Enter the Poseidon BMCL!

    For around $550 USD (+ a little for TOS MAV adapters), these puppies are by far the cheapest and cleanest option available so far. I first saw something like this dove by Richard Pyle in one of his bio pictures, although with what appeared to be an OPV mounted high on one of the stock t-pieces.

    Richard Pyle BMCL

    My configuration is as follows:
    1. Poseidon BMCLs w/o MAV adapters
    2. Low profile Tecme delrin t-pieces with 3/8" ports
    3. Tecme MAV block mounted to exhale t-piece w/ omniswivel RA connector and QC
    4. DR backplate w/ Nomad armored wing
    5. valve down bottle mounting

    Mounting the CLs was a snap. The CLs are attached to a soft plate that mounts between the backplate and wing. Only adjustment was to decide which of the 4 grommet positions to use. Since I'm 6'2" I found I had to mount the CLs as high as possible on the plate so the hoses would be comfortable. I also kept the unit mounted high on the plate for trim, same as with OTSCLs.

    The BMCLs reside way further outboard than most others I've seen and this is not adjustable. This seems to be to avoid interaction between wing and CL, but with the Nomad makes them look conspicuously outboard, like a cape. No real functional issue here.

    With the CLs mounted so high up my back it's a little tricky to reach the lanyard on the OPV, not sure what to do about this but hasn't been an issue so far.

    One funny thing is in the head down position the ADV will fire at the same time as the OPV vents. This is likely because of the cracking pressure adjustment on my ADV. I will probably increase the cracking pressure to prevent this from happening. WOB is fine.

    My view is much less obstructed and donning/doffing is much easier with these than the stock CLs. The hoses between the t-pieces and mouthpiece feel a little short (stock mediums). I plan to change to long hoses in the future to allow a little more head movement. As of now this not a problem in the water and would likely be no issue for a shorter diver.

    Removing the CLs for sterilization is a snap. Each CL is attached to a nylon-covered plastic soft plate using two double overlapping velcro straps top and bottom. It's a little tight getting to them with a hard back plate (especially the lower strap), but doable. I try to remove my t-pieces from the CLs as little as possible, so having a QC is invaluable.

    Weirdly there are two blanking plugs in the positions where the OTSCL MAVs typically mount on OTSCLs, this is likely due to the inside lung parts being the same. The instructions for using the BMCLs mention something about mounting MAVs here in the back mount configuration but I've never seen this done and could never reach the buttons I doubt.

    One other potential issue is the CL nylon covers are close enough to the edge of my SS backplate that I could see them wearing against it. I plan to find some plastic edge protection for my plate so it doesn't wear through my CLs.

    Overall very pleased with this upgrade

    Here are some pics:

    Image 1

    Image 2

    Image 3

    Image 4

    Image 5

    Last edited by missionmtb; 11th August 2018 at 08:04.

  2. #2
    RBW Member sekman is an unknown quantity at this point sekman's Avatar
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    Dec 2017

    Re: Review: *New* Poseidon Back Mounted Counterlungs

    Great post, thanks!

    Just curious, 6 months on, still happy with the BMCL? Any additional insights?

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