• Welcome to ScubaBoard

  1. Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

    Benefits of registering include

    • Ability to post and comment on topics and discussions.
    • A Free photo gallery to share your dive photos with the world.
    • You can make this box go away

    Joining is quick and easy. Login or Register now by clicking on the button

Redundant Air Source Configuration

Discussion in 'Public Safety Divers/Search and Rescue' started by Wayne at DiveSeekers, Apr 8, 2010.

  1. Wayne at DiveSeekers

    Wayne at DiveSeekers Instructor, Scuba

    # of Dives: I'm a Fish!
    Location: New Jersey
    863
    170
    43
    I know that a lot of PSD use a pony bottle. I want to get your thoughts on this.

    Side-Mount Config.

    As in recreational & tec diving as the sport evolves so do you. We believe that the next possible option for the Redundant Air System (Pony bottle) may actually come from what we do with Side-Mount. With the Side-mount config the whole system is streamlined behind you (out of the way) and if you need to take it off yourself you can. What we are envisioning is side-mounting the redundant air system and still keeping the main tank on your back.

    We use this config in caves and wreck penetration so especially with wrecks (line,cables,metal) your gear config has to be tight to prevent entanglements, so with this in mind, that's why I think that this maybe a better option over the pony config.

    If you haven't tried side-mount it maybe hard to envision this option, but I'm still curious to hear thoughts.
     
  2. ditch-diver

    ditch-diver Instructor, Scuba

    231
    7
    18
    I'm not sure of the config, I keep picturing sling tanks in my mind. Got any pics??
     
  3. muddysquirrel

    muddysquirrel Solo Diver

    26
    0
    0
    A sidemount tank is somewhat similar to a slung tank, but higher and tighter. The valve and first stages are tight under one's armpit, generally held there by a bungee, and the tail of the tank is clipped to either a waist D ring or a butt-plate.

    My recreational rig is sidemounted LP72s and it is a very light, flexible, and comfortable rig. In addition to keeping my back flexible, it keeps valves and first stages in front where it's trivial to shut down a tank or troubleshoot any problems. If I'm diving for comfort or just goofing around, SM is my rig of choice (I don't dive restrictions where it's necessary).

    Having said that... it's not my choice for PSD, primarily because of first stage entanglements. When diving with your arms in by your sides, the first stages/valves are very well protected. When diving zero vis and sweeping in the muck in front of me/over my head, the angle of my body and arm movement makes the valves much more vulnerable to having crap caught on them. When I'm pulling fishing line off myself more dives than not already, I don't want to add additional snag points... no matter how easy to clear they may be.

    I don't do wreck penetration, but I would imagine that your cable entanglements tend to be all around... thus giving SM a significant improvement in valve protection. In PSD, most of our entanglements are on the bottom... hence we protect our valves by back mounting them up away from the crap on the bottom. For those of us using FFMs with mask-mounted blocks, this also puts the primary and pony lines to the block roughly parallel and above/over the shoulder rather than coming up the chest.

    Back-mounting the pony is also a slightly faster rig to get into as well as a less dexterity intensive rig to donate (even over-sized clips can be difficult to manipulate in dry gloves in a stressful situation without substantial practice). Finally, familiarity. Not an issue if the entire team/region switches, but we try to keep all equipment, particularly emergency equipment, as standardized as possible.

    For my 2 psi... it's definitely an interesting idea, and for those who sling ponies I believe sidemount would be a significant improvement... but I prefer back-mounting the pony for PSD.
     
    Last edited: Apr 8, 2010
  4. bridgediver

    bridgediver Instructor, Scuba

    758
    5
    0
    agree with squirrel

    To add, the redundant air sourse we use are commonly just a 19 (occasionally a 30). They work much better on the back than side or slung for this reason as well as the others he covered
     
  5. ditch-diver

    ditch-diver Instructor, Scuba

    231
    7
    18
    Tks Squirrel, I do know what you sre talking about now. I have seen them and just thought it was a different style of slung tank. Not being a caver-guy, didn't know there was a differnt name. Like you, I want as little as possible hanging in or near the front of me when 'roto-tilling' in zero viz
     
  6. Wayne at DiveSeekers

    Wayne at DiveSeekers Instructor, Scuba

    # of Dives: I'm a Fish!
    Location: New Jersey
    863
    170
    43
    Everyone is bringing up good points. A lot of Side-mount photos you see, the tanks are hanging a little lower than the diver (a lot of them are larger tanks) and then your point is a valid one. If you go with a shorter bungee and have a small 30cuft bottle, you can actually float the tank back more wear it is truly on your side and behind your bicep. The tank and valve would not hang below your body what so ever. I'll try to find a photo.
     
  7. Scubadives

    Scubadives Angel Fish

    # of Dives: 25 - 49
    Location: Louisiana
    25
    0
    0
    I will join in. This is is a serious problem, but without money what can you do. When we use SCUBA,our backup is the octopus. When diving the surface supplied air mask, we use.....a small SPARE AIR!.. Im looking at getting pony bottles with the rsv-1 transfer valve. The supply line and connections to the mask are snaplock, and locking quick fittings, so if we had the rsv, and you needed to bail you switch to pony via rsv valve, disconnect from air source. The only problem there is that you have no bc. so unless you can use your supply/com/search line( they are all taped together) your gonna have to swim it up :(
     
  8. ditch-diver

    ditch-diver Instructor, Scuba

    231
    7
    18
    We tried the RSV years ago and went away from it. Just not the best solution. I'd go with a Kirby Morgan Block or something similar mounted to your SSAD harness. Then it is simply turning a knob and you are on bailout. If you need to come off your imbilical for whatever reason(extreme entanglement etc) our safety diver has a set of hook nosed bolt cutter jobbies (Kind of like for pruning branches and comes down and cuts you loose. Your power inflate comes off the block as well so you still have air to your drysuit.
     
  9. Scubadives

    Scubadives Angel Fish

    # of Dives: 25 - 49
    Location: Louisiana
    25
    0
    0
    Whats a drysuit? I live in Louisiana! lol It does get cold I have recovered a boat and assisted with recovery of a body in 45 degree water with just a wetsuit. I only went down once, then got changed and dry, but shivered the rest of the day trying to get warm. From that point on we amended our sog to cease dive ops at a certain temp until we get dry suits.

    As far as the valve goes, I was only mentioning the rsv as type and function, not that I was set on that brand since I have not researched them all. We have twist-lock and push air connections, and our lifeline is tethered with a snap shackle and a "monkeys fist" handle to release it. I would not want my guys depending on someone from the surface to bring bolt cutters down just so they could bail out.

    Money has us pretty hemmed up. I am actually unnerved about how many different things that could go wrong with our setups, would love to have a really experienced PSD instructor come out and evaluate our setup, and let us know what is good, what is a death trap, and what to do from here......
     
  10. ditch-diver

    ditch-diver Instructor, Scuba

    231
    7
    18

    Is that an offer?? :eyebrow:

    I didn't explain very well, the bolt cutter scenario if for when diving surface supplied and you are hard wired into an imbilical. Sorry man.
     

Share This Page