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DIR "compliant" twindies config?

Discussion in 'General Scuba Diving' started by Wibble, Nov 20, 2018.

  1. Wibble

    Wibble Fish don't talk
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    Spurred on by a recent boat trip where a geezer was wearing an unbelievably complex twinset rig with four first stages, a ponied 7 litre deco tin and a slob-knob, not to mention all the dangly gauges...

    What would a DIR-inspired twindies config look like? (Twindies = twin independent cylinders) Yes, I know there's no such thing, but just as an exercise in WTF. Kind of thinking the sort of thing you could take to some far-off place where there's no manifolded twinsets, but there is low-pressure gas and a lot of other novice divers around, so you take two tins, strap them together, then see what happens.

    The closest I can think of would be like a Sidemount config, where there's a bungeed single short hose, a long hose and two gauges. As they're singles, you'd end up with one 1st stage sticking "out" (the LHS) as the tin would be twisted around so you could manipulate the knob. There would be two SPGs with the RH one clipped to an "additional" RH waist D-ring.

    You'd use this in a similar way as per sidemount, breathing 60 bar(ish)/side. A donate is with the long hose, which would be clipped on the RH chest D-ring when not in use.


    Anyone tried a mongrel config like this? Any links to a suitable "Twin Tank Adapter" that would fit a backplate?

    What other alternatives would there be "when diving abroad". Sidemount's an option, but not really if they're the horrid fat tins.
     
  2. Nick Ward

    Nick Ward Active Member

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    I think indy 12's (and 7's) are a fairly common set up aren't they? I've certainly seen quite a few in the short time I've been diving

    As per usual - I don't think there's a standard, but the common set up is not dissimilar to manifolded twins, with the addition of spg on the RH valve clipped to side, and often an additional octopus...
     
  3. Nick Ward

    Nick Ward Active Member

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  4. Vanny

    Vanny Active Member

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    Yes like Nick said , fairly common. I started my journey to twin set Diving with some AP twin set bands on my buddy commando. Indie 12’s swopping regs every 50 bar or so I remember. I think initially I just stuck the wife’s regs on the “ new” cylinder so had tons of crap. Then cut back to what Nick suggests.
     
  5. jb2cool

    jb2cool Moderator
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    If it's twindies then it's not 'DIR', simple, stop trying to shoehorn things into the wrong box. This isn't to say that you can't set up a twindies setup to your satisfaction but there sure as hell won't be a standardised 'DIR' twindies setup for it. I think in your scenario I'd lean towards a bottom stage and then a standard single setup. Then again if the place I'm diving doesn't have twinsets and the gas is not that great a pressure do I really want to be doing bigger/longer dives here? Why did you book to go there if they are not set up for the diving you want to do.

    What I don't get is that since you are not a DIR/GUE diver is why you care? Just rig something up that works for you and go for it but don't try and pass it off as some kind of standard. There is nothing new about diving twindies.

    I wonder if you could bodge something together with a couple of these and a decant/fill whip.

    [​IMG] [​IMG]
     
    #5 jb2cool, Nov 20, 2018
    Last edited: Nov 20, 2018
  6. Alex Denny

    Alex Denny Active Member

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    I’m off to the Maldives in January and almost certainly diving twindies as no doubles available. I’ll be using an AP tekwing and standard twin set regs. If you want to go really posh in a wetsuit, get a an AP redwing to go with the tekwing and you have a full independent buoyancy setup. (I used exactly this dual bladder setup in the Red Sea last week, albeit on proper manifolded doubles. Tekwing s are great travel wings as no heavy metal back plate),

    For twindies, on holiday, I personally wouldn’t bother turning one of the cylinders backwards. If you can reach a manifold in the centre wearing a drysuit, you can almost certainly reach a standard right hand valve on the ‘wrong side’ in a wetsuit (just remember to turn it the right way!) and in any case, if you don’t manage to shut it down, you’re only going to lose that cylinder of gas.
     
  7. Alex Denny

    Alex Denny Active Member

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    I’m sure there’s another thread about that somewhere. (I know there is an old one on Scubaboard filled with Americans). In the past, I’ve considered the same thing.

    The problem with this is that either a first stage or second stage regulator free flow means total gas loss. True - you can shut off a cylinder, but you can’t stop total gas loss from the other one, and then can’t breathe the one you closed off. Better to just stick with them as independent.

    Otherwise, you can get an old “cheater bar” non-isolation manifold and use a standard single reg setup and at least remove one of the first stage points of failure... But why not just dive them independent? Or sidemount. (Or buy a rebreather)
     
  8. Wibble

    Wibble Fish don't talk
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    @jb2cool - by "DIR", I know that by definition any changes mean it's not "DIR". However, one of the great things about a DIRish (can I use that word, no, let's call it "DIR inspired") is that things are where you expect them to be. In most of the warm water places I've dived, it's recreational all the way: no twinsets available, and definitely no stages!

    On my single wing with single tank adapter, aside from the obvious lack of shutdown ability, pretty much everything is in the same place and one can almost believe that it's a twinset.

    With my Sidemount rig, there's a necklaced short hose and a longhose routed around my neck; very DIR-like. OK, the longhose is bungeed to the cylinder and it's a completely different config.... hmmm.

    I've heard that diving in Cyprus means single tanks and 200 bar considered as a 'good' fill -- TBH I've had similar experience in Spain. The benefit of using 'twindies' is for the redundancy and reserve gas, especially useful if diving alone, with novices, or at night. It's not really to dive deeper/longer.



    Anyone have recommendations for a "twin tank adapter" that will fit to a standard backplate?
     
  9. jb2cool

    jb2cool Moderator
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    Did you not see the hand wheel on the whip? It allows you to close off the whip and use it as an isolator.

    I'd still favour doing this as a bottom stage. Sure the cylinders may not be rigged up as a stage already but you can always take a stage kit with you.
     
  10. nickb

    nickb Active Member

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    Yep, all of this is spot on.

    I've never seen an indie twinset that I would consider anything other than an exercise in demonstrating that the owner doesn't give a fuck about being a thinking diver that aspires to be any good. Most look like they just cobbled together whatever old tat that was left at the back of the club's hall of shame.

    Rather than trying to invent the dream setup with indies (doesn't exist), let's submit the worst we've ever seen. Recently we had one with differing sized cylinders, one A-clamp, one DIN, different first and second stages attached to an old, faded Buddy stab jacket. You can guess what kind of other junk that was attached to it...

    There are many more great diving destinations that could satisfy my kit requirements than I'll live long enough to get the opportunity to visit. I don't need to come-up with a shit-show kit setup so that I can dive the bad ones.

    @Wibble this has to be your worst-ever thought experiment and you have a track record of some real howlers.
     
    timmyg, Dave Whitlow and Wibble like this.
  11. Alex Denny

    Alex Denny Active Member

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    I had missed that. Sorry. I still think it’s overcomplicated compared to standard independent twins - especially if the core aim is redundancy.

    I can’t agree with that. If twins actually aren’t available, I can’t see any situation where twindies aren’t safer than singles.

    My setup on twindies overseas is pretty much the same as a ‘proper’ twinset apart from it uses cambands. It’s all properly serviced, good condition and matched (not that it really matters) and I think very well thought out as a travel set.
     
  12. nickb

    nickb Active Member

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    Bollocks. Jason has already outlined a better solution, which is also DIR (a requirement of Wibble's ridiculous thought experiment).

    A single wing and cylinder with long hose and necklaced backup reg along with a normally-equipped bottom stage will offer a far better solution than some cobbled-together shit show. Assuming you can source two cylinders (pretty much a pre-requisite for a dive centre anywhere on the planet), you can bring all your own gear rather than relying on whatever crap the venue happens to have.
     
  13. John F

    John F Member

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    Blimy Glen, lite blue touch paper and stand back.
     
  14. Alex Denny

    Alex Denny Active Member

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    What’s cobbled together with a tekwing and twinning bands as bought from a shop, used exactly as designed, with two first stages, long hose and short hose on a necklace?

    I way prefer that to the extra drag of a stage. It may not be ‘DIR’ but it is well understood, common, effective and has at least one fewer failure points than a single cylinder and stage cylinder as you have fewer second-stage regs?
     
  15. Doomanic

    Doomanic Dinosaur Wrangler
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    What diving in the Maldives warrants twins?
     
  16. Alex Denny

    Alex Denny Active Member

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    I guess that's a fair question. As I understand it, recreational diving limits in the Maldives are officially 30m regardless of qualifications.

    As a general rule, I avoid doing any dives over 30m without redundancy and would default to twins or at least a second cylinder of some sort. This may not apply here but most dives will be near 30m at least.

    BUT: the cost of an extra 12l cylinder is about the same as an upgrade toa 15l cylinder. My twinset regs are better quality and more familiar than my singles. Apart from an extra first stage and SPG, they don't use much more space or weight.

    On that basis, why would I not twin up? Otherwise it seems an unnecessary compromise on safety that I would not accept at home.
     
  17. Doomanic

    Doomanic Dinosaur Wrangler
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    Because you won't be exceeding your requirement for redundancy. Why make life more complicated than it needs to be?
     
  18. Alex Denny

    Alex Denny Active Member

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    How is it more complicated though? It’s a live aboard. I strap two cylinders on, on the first day, instead of one, and leave them there.

    True, I will almost certainly not need the redundancy on the trip. But if I do get a free flow or something else goes wrong, I have redundant gas and twice as much as if I had the single 12 included in the Blue o Two package price.

    I’m not likely to need a spare mask or line cutter. Still taking them though.
     
    Wibble likes this.
  19. Doomanic

    Doomanic Dinosaur Wrangler
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    To me it just seems like Wibble levels of faff for the dives you'll be doing.
     
  20. Alex Denny

    Alex Denny Active Member

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    Ah, well I do have another excuse if it helps. Just back from the Red Sea (as mentioned above) where we did some deep diving on ‘proper’ twins (albeit with cambands on the tekwing as mentioned, rather than screwed to a backplate). I haven’t unpacked the gear yet. I probably won’t bother.

    It’s actually less faff to dive twindies than repack everything for singles.

    In the meantime, my drysuit / cold water gear is all ready to go in the UK.
     

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