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Aluminum 80 fix?!?

Discussion in 'Sidemount Diving' started by Doby45, Aug 12, 2016.

  1. Patoux01

    Patoux01 Solo Diver

    # of Dives: 100 - 199
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    I'd just buy 2 d-rings and stoppers and be done with it, but that's just me.

    Also 80s can be used as main tanks without problem, I do that, because I look for the neutral behavior of aluminium tanks.

    Except that, sure, go ahead. You'll probably find people silly enough to buy and carry a 5# weight with them when travelling to places where they cant find steel tanks.
     
  2. Filthy1

    Filthy1 Angel Fish

    # of Dives: 1,000 - 2,499
    Location: British Columbia
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  3. Filthy1

    Filthy1 Angel Fish

    # of Dives: 1,000 - 2,499
    Location: British Columbia
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    I threaded a 2 1/2 lbs bullet on my tank strap. That seemed to take care of that.
     
  4. DevonDiver

    DevonDiver N/A

    # of Dives: 5,000 - ∞
    Location: Subic Bay, Philippines
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    I don't really get this whole "mimic steel' philosophy....?!?

    From now on, I am gonna call it the 'alchemy compensation'....

    Cylinder selection is part of an overall weighting strategy. Divers opt for steel tanks because it removes and distributes excessive weight from the torso. That's why steel tanks are predominant in cold and temperate water climate areas.

    In contrast, aluminum cylinders are ubiquitous in tropical regions. In warm water regions, thinner exposure protection does not necessitate vast amounts of weighting. As such, the cylinders do not form part of an overall weighting strategy...... except for those who routinely dive grossly over-weighted....

    For sidemount in particular.... there are benefits to aluminum cylinders... in that cylinders can be added, removed and handled in-water without any gross impact on diver buoyancy or trim.

    Trying to mimic steel with weighted aluminum for the sole benefit of tank trim.... seems to me a most short-sighted 'equipment fix' to a skills and configuration problem. Really....

    To trim aluminum cylinders.... we're talking about.... what? Moving two bolt-snaps once during a dive. Is that such a big deal that it's worth screwing up your integral balanced rig for?? Is it beyond your skill-set and competency range???

    Now.... some divers find it problematic to 'simply move between two bolt-snaps'.... and that's because they've chosen an inappropriate mounting method, the wrong sidemount BCD design (i.e. a cold-water/American style rig with rails) and/or ineffective bungee method.... and they cannot make aluminum cylinders 'work' with the kit they've mistakenly opted for.......
     
    BeijaFlor and cerich like this.
  5. DevonDiver

    DevonDiver N/A

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    It's a performance requirement on PADI sidemount courses, regardless of cylinder material.

    It's also a performance requirement on many sidemount overhead environment courses....

    On my courses, we do complete remove/replace of cylinders underwater (maintaining neutral buoyancy and trim).;... anyone wanting to do that with weights on a aluminum cylinder is gonna really make me chuckle :wink: I also do skills where one cylinder is removed and staged, then the diver completed a circuit with a single cylinder, before returning to collect and don their second cylinder.... again, major problems for those who've short-cutted with some cylinder alchemy.... :)
     
    BeijaFlor likes this.
  6. Doby45

    Doby45 Do I have something in my teeth?

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    Once again we find someone that is reading way more into this than there really is. let me see if I can break it down AGAIN as to the rational of my decision.

    1. I have spent a crap ton of money on scuba this year and simply will not be justifying the purchase of a couple HP100s. Hopefully, those will be in my 2017 scuba budget.

    2. I am not in a tropical area (hard to believe I know) Much like I have seen you say that Florida cave divers think the way they think is global and it isn't. The way you think "tropical" is not the same all over.

    3. I currently have two perfectly matched Luxfer 80cf tanks and for now that is what I will be training in my cool quarry with in a drysuit. I want these tanks to behave as much like a steel as possible, because that is what I am going to be using (eventually).

    4. I want my solution to be "streamline" and not some chunky weights just hanging on a band.

    5. I have plenty of lead to do this with.

    6. This is not a permanent modification to the tanks and when I do get my steels these can easily be removed and the 80s used as stage tanks..

    Any other questions as to why I am doing this? And for the record I have not even had time to go out and melt some lead since I posted this, been busy.
     
  7. DevonDiver

    DevonDiver N/A

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    What I read was...

    ....which indicates that transfering lead from the weightbelt to the cylinder was an attempt to address cylinder buoyancy/trim issues.

    My reply merely indicated that this solution was illogical and unnecessary, given more preferable, proven and long-term beneficial solutions to the issue of aluminum cylinder buoyancy.

    If, however, this is a temporary convenience (budget for steel tanks pending).... instigated by a weighting strategy for cold water diving, then it makes more sense. i.e. that your primary aim is to remove lead from the weightbelt and distribute it elsewhere.... However, that's not what you said... :wink:
     
  8. cerich

    cerich ScubaBoard Supporter ScubaBoard Supporter

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    well... I am not a PADI SM instr.. nor I guess likely to be one.

    I have no issue with the skill when it isn't dangerous, doing it with steel cylinders is, and in my world lots of people dive steel.

    Have you taught a SM class with steel cylinders?

    By the way, your comments on diving the right rig to your cylinders is correct, trying to make a system that was designed for alm 80's work with heavy steels or vice versa is always a exercise in frustration.
     
    BeijaFlor likes this.
  9. DevonDiver

    DevonDiver N/A

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    Not taught a class with them, but have used them for the 'professional development' value.. as some of my students will use steel when they return home to colder climates... and I need to educate them accordingly.

    What size bungee for what size/relative weight cylinder? Optimum bungee methods? Band positioning? etc etc etc.... all stuff that has to be 'taken away' when going home from the tropics to cold water... (and should be taught vice-versa by cold-water SM instructors preparing students who may subsequently dive in 'aluminum ubiquitous' holiday destinations).

    I drew the line at twin steel 20 litre tanks...but do wonder if the higher capacity 'Mexico system' rigs would support them.... one for a rainy day...and if the owner lets me strip them down from doubles...

    I generally dive wetsuit here...with 4lbs (3mm) or 12lbs (5mm) weighting... so steel tanks pose some serious 'balanced rig' issues. Same for my students... Also... there's only one dive center that I know of in the northern Philippines that actually has steel cylinders... LOL
     
    Last edited: Aug 31, 2016
  10. MSargeant

    MSargeant Nassau Grouper

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    I had your issue a couple years ago when I first started diving sidemount. Cold UK water + ali cylinders + drysuit/undersuit = about 12kg. Was a bit naff. wondered whether i should weight the tanks to stop them swinging.

    Then I spent a little under £10 for some sliding D rings and just adjusted them as and when. Happy days.

    By all means cast the boot weights and make your alis act like steels, but you lose all the fun properties of ali cylinders, second set of D rings costs next to nothing and you can keep practicing for the holidays.

    P.S. Swapped to Steels a month ago. Little less ballache, liking the smidge extra gas.

    If I were you I'd cast some weights and flog them to friends.
     
    rjack321 likes this.

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