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SPGs on CCRs

Discussion in 'Rebreather Diving' started by doctormike, Apr 22, 2019.

What sort of tank pressure monitoring system do you use on your CCR?

  1. Stock SPGs, Front Mounted

    30 vote(s)
    55.6%
  2. Stock SPGs, Back Mounted

    6 vote(s)
    11.1%
  3. Wireless transmitters

    6 vote(s)
    11.1%
  4. Wireless transmitters and SPGs

    2 vote(s)
    3.7%
  5. Button SPGs

    5 vote(s)
    9.3%
  6. None

    4 vote(s)
    7.4%
  7. Other aftermarket SPGs

    1 vote(s)
    1.9%
  1. CptTightPants21

    CptTightPants21 Solo Diver

    # of Dives: 200 - 499
    Location: NY/NJ
    1,037
    543
    113
    Same. Demoed an XCCR and liked it a lot, but the costs seem really high when compared to other CCRs.
     
  2. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    8,963
    2,814
    113
    I have never run out of wing gas but I have run out of suit gas a few times. I have also splashed (on OC) with suit bottles off. There is a non-zero chance of jumping in with the onboard suit/wing gas bottle off or so close to empty you drain it. Since this is a thread about SPGs I'll vouch for accidentally using a empty or near empty one as the most likely issue. But you could have a leaking OPV on the first stage (those little things are a necessary evil but junk), ruptured LP hose isn't unheard of as well. In my experience burst disks rarely blow but they sometimes leak, if its been leaking since it was filled then your bottle might be closer to empty than full. There's lots of ways that suit/wing bottle could either start out or empty quick.

    With 2 or 3 BO/deco bottles on you are at least 10lbs negative and likely more like 18-20lbs negative (2x al80s + al40). You can swim that up, sort of. 3x al80s + al40 is not really swimmable IMO. You sink really fast and messing around in your pockets is not really doable in a timely manner. Orally inflating with a CCR as you sink is not good either, you're probably going to partially or completely flood the loop as you screw with the DSV and rely on the ADV to make up the volume. Unless you're like me and you always have your ADV (which doubles as my dil MAV) off on the surface to avoid hypoxic dil leaking or otherwise not having a loop full of O2 at and near the surface.

    Net you're pretty hosed to be dropping like a stone, loop volume is shrinking fast, you can't breathe, your lung volume is smushed so there's little or nothing to exhale into your wing manually, and you have no buoyancy.

    There's a lot riding on that backmounted bottle of wing and suit air. Its a single point of failure that has a ton of really bad consequences if all the holes in the cheese align. In a cave with a floor, yea you faceplant which is pretty bad. But its not fatally bad. In the ocean bring independent sources of buoyancy like you would on OC.
     
    blake7, taimen, JonG1 and 1 other person like this.
  3. Reku

    Reku Solo Diver

    # of Dives: 5,000 - ∞
    Location: Great Lakes + Northern Florida + Marsh Harbor
    860
    308
    63
    Exactly - I actually always do a prebreathe and pos/neg check and a few other checks. If I'm doing any of the checks I do all of them. So when I say I'm prebreathing - it really means I'm going through a huge list of checks.

    I just think it's completely insane and stupid to not do prebreathing and the handful of checks you should do in order to assure that your unit is working correctly. It's minutes out of your life for hours underwater.
     
    doctormike and Doby45 like this.
  4. nung1009

    nung1009 Angel Fish

    # of Dives: 100 - 199
    Location: New York
    14
    2
    3
    Just out of curiosity, where did you get the needle valve?
     
  5. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
    8,963
    2,814
    113
    I use a fathom needle valve, I got that simple one direct from Charlie Robson.

    Chris Kennedy will also make you a simple to a fancy custom one with a dil MAV included if you want.

    Mike at KISS has a few prototypes out in the wild but he seems to not want to put a needle valve into mass production
     
    nung1009 likes this.
  6. uwxplorer

    uwxplorer Rebreather Pilot

    # of Dives: 500 - 999
    Location: Los Angeles
    233
    117
    43
    Ever thought of routing them behind your arms and clipping to the crotch strap? Works like a charm. Some would say entanglement hazard, but with two bailout tanks, there are other things that will snag on first. That has happen to me once on a swim step though... No big deal.
     
  7. Jeremy Williams

    Jeremy Williams Nassau Grouper

    156
    75
    28
    I’m not sure about that. Subgravity only sells it with regs and tanks and BOV so it may seem high. Once you compare apples to apples on a new unit it doesn’t really seem to me to be much more than a comparable JJ or SF2 or Prism. All of those seem to settle out pretty close to $10k too.

    Capital Costs between units

    Is there a comparable units that’s lots less? I don’t see it unless you are comparing to a used Prism which really can be had for much less.
     
  8. nung1009

    nung1009 Angel Fish

    # of Dives: 100 - 199
    Location: New York
    14
    2
    3
    Thanks!
     

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