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What size stage?

Discussion in 'Technical Diving' started by Zubar, Dec 11, 2011.

  1. Zubar

    Zubar Active Member
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    I am toying with the idea of getting a stage for limited deco dives. (have qual to 48m)
    I trained with an ali 80 (11l?) but found it quite big.
    Should I just go for this and get used to it or would a smaller one be ok?

    Ta much

    C
     
  2. Suggsy

    Suggsy Banned

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    I don't know if Dave will allow me to answer but I shall anyway.
    The answer all depends on how much deco you have planned for, the deco gas and your SAC rate. If you're anything like the kit whore I am you will end up with an ali40 an ali7 and an ali80, just because! :)
    I use a 7lt mostly for dives in that range and 50% deco gas. Saying that though I recently had my 80 resprayed and put back in test. It gives a bit more flexibility and floats nicer once down to about 120bar. Oh and old 7lts are thinner walled so float better, but you'll find, as with anything governed by supply and demand, they command a higher premium.
     
  3. Silty Bottom

    Silty Bottom in DIRnial

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    Mmmm shiny stages
     
  4. Roy

    Roy Active Member

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    I'm very happy with a steel 7.
     
  5. Zubar

    Zubar Active Member
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    So you say get a selecion, I like it!:cool:

    If I obey the law then I am limited to 15 min deco on any mix, low sac rate. Have used 50 so far.

    I would rather ali.

    C
     
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  6. j_b

    j_b Well-Known Member

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    Can you squeeze that to 15 mins PER mix?! ;)
     
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  7. big si

    big si Well-Known Member

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    I use ali 80s for a few reasons, more gas volume and I stack all my stages on the left so I need cylinders that are more balanced and not far off neutral, so if you only have 190 bar at the beginning of the dive ali 80s are perfect cylinders that dont make you feel left heavy.
    I no they seem quite big on land but in the water even with two clipped of to the left I dont ever notice thier there, I also tuck the tail and clip round through the handle of the rigging to shorten it so it pulls the cylinder closer into the hip.
    Iv got a 7lt and hate the damn thing.
    Also look at where your diving is heading if you think its going to be deeper and deeper and longer then ali 80s for more gas volume are the cylinders you realy need.
    An ali 80 is also a good cylinder to use on extended range type dives to say 55m where there is enough gas volume for deco on 50% (SAC dependant) with only a few more minutes deco than using two deco gases and carrying two deco cylinders, you cauld use an ali 40 and a 7lt ali for the same dive but it just weighs abit more and two cylinders to fiddle with. Using 50% and 100% or 50% and 80% will get you out the water quicker but its something to think about theres nothing set in stone.
     
  8. big si

    big si Well-Known Member

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    Through the 15mins out the window.
     
  9. Silty Bottom

    Silty Bottom in DIRnial

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    Has anyone ever stuck to that mystical 15mins when qualified?

    Which agencies still qualify you to limited deco?
     
  10. big si

    big si Well-Known Member

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    I dont know anyone who has done ART if I was asked which course would be best as a stepping stone into technical diving I would suggest TDI advanced nitrox/ deco procedures / troix with the helium content of 20% a much more useable gas IMO with no restrictions on deco and if you fancy diving beyone your cert then its a useable gas down to 57m if you choose but that only my thoughts.
     
  11. Major Clanger

    Major Clanger P-Plated Meg Diver

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    Down to 48m the seven ali is ideal using something like a 50 or 100 for deco.
     
  12. Silty Bottom

    Silty Bottom in DIRnial

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    AG did ART with Andy Boyle last year.

    The only reason I did adv nitrox was Andy Hayhurst was offering heavily discounted courses while he was training a new instructor and we were his guinea pigs :) otherwise I was going down the ART route.

    As it happens the only limit on my qualification is two nitrox mixes. But then some on here would say it isn't a real qualification with a real agency anyway ;)
     
  13. big si

    big si Well-Known Member

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    Oh yes I understand that one Kev;)
     
  14. Zubar

    Zubar Active Member
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    Thanks thats what I suspected. Will look at an 80.

    ART will serve me fine for the moment. I also realise the cert levels are somewhat flexible but happy to work to them for the moment.

    Hey, I could have done worse. Don't padi do tec? ;)

    C
     
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  15. Jenkins

    Jenkins Friends, Romans, countrymen, lend me your ears.

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    What size twins are you using and what is your SAC rate? These will both affect the option size for your stages.

    FWIW Wrekrab and I both dive twin 12's and two steel 7l stages.
    On a 60m dive dictated by available botom gas we can both comfortably get 3 dives from the travel gas/leaner stage and just get three dives out of the rich/deco stage - by just I mean yes its is safe and we have adequate redundancy, but Wrekrab (who breathes more than me) prefers to fill after 2 dives as he doesn't like seeing the guage reading that low ;))
    On shallower dives (what you are looking at) we could comfortably get 2 dives out of one 7l stage containing EAN50.

    So given that you are rather better on air than us I suspect that an ali80 (10l) cylinder is probably OTT at the moment and even if/when you move deeper it will still hold more gas than you need for a single days diving.
     
  16. big si

    big si Well-Known Member

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    Nowt like planning your dives with gas in resurve then? just incase your buddy looses one or more deco gases ;) remembering rule of thirds on bottom gas and rule of half on deco gas, I know one ascociation has a slightly different take on how much gas will get you out the :poop: but im sure Zubar wont have any knowledge of it and as hes only just moving into technical diving surely talking more gas rather than less gas might be more benificial to him, remembering no one has ever died from having to much gas.

    Steel 7s are much more heavy in the water so you cant stack them both on the left so if hes using a long hose primary donate which im sure is taught on the ART course the cylinder will impeed the donation process of the long hose. :) plus having one heavy steel cylinder hung on the left will cause unbalance.
     
  17. Jenkins

    Jenkins Friends, Romans, countrymen, lend me your ears.

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    Sorry? I always carry enough gas INCLUDING at least the necessary reserve for redundancy.

    Oh dear I am going to die a horrible death - someone strike my instructor off the IANTD database, for teaching me to dive with a stage on each side coupled with a hogloop :devil:

    Oh, no, wait, I remember now! We did this funny thing called an S-drill, where after clipping our stages on we deploy (and if necessary untangle) the long hose so it lies over the stage and is completely unrestricted and able to deploy perfectly :frog:

    Yep not everyone likes steel stages, but personally having used both prefer a dead weight hanging to a floaty ali cylinder - personal choice.
    Yes it's probably uncomfortable if you have two steel stages on your left (as I said I balance one each side), but when diving with just one stage I certainly don't find that the extra weight of a steel 7l unbalances me.
     
  18. big si

    big si Well-Known Member

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    I maybe misinterpeted you post as you said your dive was dictated by you bottom gas on a 60m dive and that you could get 3 dives out of your deco cylinders, im just wondering surely if you had full twin 12s at the start of a 60m dive and you had already had 2 dives or even 1 dive out your deco gas you should plan your dive to what available gas you have as deco gas? Unless you have a SAC af about 2 lts per min during your deco phase, then of course you need to take into account of your buddies SAC on deco for lost gas. You even say its safe, just. In your own words there I feel you dont realy believe its safe?
    I think when you come to deploy your long hose in anger it might not be as easy as you pridict id put money on it.:)
     
  19. Suggsy

    Suggsy Banned

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    Huh? You ask his SAC then a couple of sentances later you say an Ali80 would be OTT? Oh and they are 11.1lt NOT 10lt. Plus how do you know how much gas he needs if you don't know his SAC as you asked at the beginning of your reply?

    I would state that to conduct a deco dive to 60m you should really be taking a full stage, especially if its a 7lt, even better, take 2.
    In the event of elevated breathing rates due to a shit/fan interface i'd rather have too much gas than not enough, not until I've mastered this breathing water malarky.
     
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  20. Silty Bottom

    Silty Bottom in DIRnial

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    I'm firmly in the same camp as big si on this one in that no one ever died from having too much gas. The first few deco dives are always going to be a bit unnerving with your sac rate through the roof. Add in a little narcosis, possibly throw in a buddy like AG and it's nice to have an excessive abundance of 50 in the deco cylinder :)
     
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