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SM Boat diving, Gas switching block

Discussion in 'Technical Diving Specialties' started by afmiller, Jun 12, 2019 at 10:23 AM.

  1. AJ

    AJ Solo Diver

    # of Dives: 500 - 999
    Location: Netherlands
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    Well, may I suggest to start early doing things by the right procedure (meaning future way of diving) or stay with FFM and rec diving. You will be a lot happier when you're used to doing things the tech way later on. Has to do with muscle memory.
     
    rongoodman likes this.
  2. tbone1004

    tbone1004 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
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    @afmiller good reason for FFM

    If you're boat diving in the northeast I would really recommend diving doubles instead of sidemount.... A million reasons why, but doubles are better for boat diving. I have been sidemount diving for 10 years and I still dive backmount in open water, especially when dealing with multiple bottles.

    When you start diving with deco bottles, you are a going to have to find an instructor that will teach you in a FFM. I own FFM's and can teach the course for them, and I can teach andp, but I will not do it. Very few instructors will and you'll be hard pressed to find one. There was actually a thread a few months ago about doing andp in a FFM and I don't think anyone found one that would.

    The complications were beat to death in that thread though.

    @decompression very different than the UTD "solution" though since that isn't a switch block, just a manifold.
     
  3. michael-fisch

    michael-fisch Barracuda

    # of Dives: 2,500 - 4,999
    Location: Germany
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    Years ago, I had an Interspiro FFM with the overpressure spring, and a DSI EXO26 FFM.
    The best day of my life was the day I sold both of them to someone else.
    Why?
    Breathing against the overpressure spring was hard on the Interspiro at the surface, and my air consumption was about 30% higher.
    The 5 point harness on the EXO26 forced the mask far enough back that my jaw hurt after 45 minutes, the air intake over my eyes did a good job of keeping the mask from fogging up and a great job of keeping my face very cold, and breathing in it was almost as loud as a day at the shooting range with a 2.5" 357 and hot loads - in other words it was way too loud!
    Currently my only use for a FFM would be for use with O2 in IWR, and even there it isn't ideal since drinking liquids with a FFM isn't forseen, and a DSI (Kirby Morgan) Bandmask would be more comfortable.

    Michael
     
  4. tbone1004

    tbone1004 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
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    @michael-fisch mine is with me on every trip for IWR and is the reason that it has a gas block. Gas block is obviously needed for IWR, both for gas switching, but also just connecting to whatever is available. I use QC6's for my CCR so everything has one on there which means any bottle can get plugged in for air breaks, or extra O2. The only other time I use it is when I need comms on working/training dives, and those are relatively infrequent. I have a Poseidon Atmosphere which I have set up to not be positive pressure since I don't dive in contaminated water and it's great, but not something I choose to use.
    If I was ice diving then I'd probably use it for that, but I try to avoid cold water if I can help it.
     
  5. afmiller

    afmiller Angel Fish

    # of Dives: 50 - 99
    Location: New York
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    @tbone1004 , I would not do andp with the FFM. I would only use the FFM recreationally with the wife at that point. The wife doesn't want anything to do with deco. The shop up here is actually wants to set up some Ice diving this winter, which I am interested in trying. Can the SMS 75 handle BM doubles? What Backplate do I need to use? Also how does the SMS 75 handle Single BM?

    I found this from omni swivel. Didnt realize they had that kind. Currently wuse a QD from them on the Single BM setup

    Quick Disconnect Set: Streamline & Check Valve
     
  6. tbone1004

    tbone1004 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
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    SMS75 can hold doubles and singles. Doesn't do doubles well since you are already head heavy in doubles and all the lift in the 75 is at the hips, but it can be made to work. No extra backplate with the SMS75 for backmount.

    I'm doing some prototype diving with Omni right now but that check valve isn't a DESO like the QC6 is. It is meant more for use on manifolds than in this application since it will still let water in as you descent. I use their QD's on my actually FFM, but I do not use them anywhere else because of the lack of DESO.

    So circling back.
    You currently dive FFM and want to continue to dive FFM.
    You are wanting to do sidemount off of a boat in the northeast for some reason, and you want to make that work with FFM.
    You are wanting to do sidemount now in anticipation of ANDP, but continue to use your FFM
    That right?
    In that case you're in a strange pickle right now with using the FFM and sidemount together when you need neither.
     
  7. afmiller

    afmiller Angel Fish

    # of Dives: 50 - 99
    Location: New York
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    #1 I am currently using the FFM
    #2 The jury is still out in regards to the boat. Alot of the diving around me I can do SM without a boat. Haven't been up the St Lawrence yet (So don't know about that) The original question was about making it easier if it does happen, cause with the hard connections its not practical at all, as both tanks/regs and gear minus the FFM are attached in one way or another.
    #3 You are correct for SM now and doing ANDP next spring / summer. As for using the FFM. I wouldnt use it when doing those dives as it adds a layer of complexity that I would view as not worth the risk in bottle management. I would only continue to use the FFM recreational wise with the wife / but when doing Deco dives, I would not.

    In regards to the QC6, what do you mean by DESO?
     
  8. rjack321

    rjack321 Captain

    # of Dives: 1,000 - 2,499
    Location: Port Orchard, WA
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    DESO = double ended shut off

    QC6 is one of the few high flow connector type in diving with a valve that closes when disconnected on both ends.
    Male goes on the cylinder whip
    Female goes on the inlet

    FFM and sidemount with an SMS75 on a boat is a hot mess.... I sidemount, in an SMS75. But not off a boat and not with a FFM. I also have hundreds of hours in an AGA FFM. Combining all this at once? Silly and convoluted.
     
  9. tbone1004

    tbone1004 ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: I'm a Fish!
    Location: Greenville, South Carolina, United States
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  10. afmiller

    afmiller Angel Fish

    # of Dives: 50 - 99
    Location: New York
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    Thanks rjack and tbone
    Trying to figure out what will work best, it looks like I will go with the QC6 for the non boat dives and stick to the BM for Boats.
     

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