• 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

A Case for Spare Air

Discussion in 'Advanced Scuba Discussions' started by certainmisuse, Mar 28, 2019.

  1. certainmisuse

    certainmisuse Nassau Grouper

    # of Dives: 100 - 199
    Location: Atlanta GA
    146
    15
    18
    I agree if that's the case, but I simply don't have one.

    For the record I used to do cold water diving, a lot of it solo, with a backup 30 cu. ft. Now I'm moving to shallow warm, shore diving exclusively. Its more of a discussion of how much gas do you need, and less about why I may or may not add redundant gas given the shallow depths. I will likely add extra gas by default.
     
  2. TMHeimer

    TMHeimer Divemaster

    # of Dives: 500 - 999
    Location: Dartmouth,NS,Canada(Eastern Passage-Atlantic)
    11,705
    2,407
    113
    I have a 13 cu ft pony which I consider using on the rare deeper dives I do. I need no pony or Spare Air for my normal dives of 30' or less, as I regularly practice CESA from those depths (there was a whole thread on why you should/shouldn't practice CESAs). I see no point in buying Spare Air when I don't need it. Plus one more item to rinse.
     
  3. Will_A

    Will_A Angel Fish

    # of Dives: 50 - 99
    Location: Los Angeles, CA
    9
    17
    3
    Hey all!

    I know I'm going to catch hell for saying something in favor of Spare Air. But I've been using one and testing it out for about a year and a half now and I thought I'd post some observations. When I go diving if I haven't used my Spare Air for an emergency purpose (and I've never needed to) on the last dive of the trip I test it out at depth simulating an out of air emergency and then breathing it until empty. I've tested them at depths from 20' to as far down as 130'.

    First. As everyone agrees, you probably shouldn't need it. Gas management. Proper buddy technique and all that. But the truth is people do find themselves in OOA emergencies either through their own negligence or out of no fault of their own. And, if you are travelling to new locales and diving without a regular dive buddy (as I do, frequently) your choice of buddy may not be ideal. You aren't functioning like a well-oiled machine.

    Here's some scenarios where Spare Air makes sense to me.

    Scenario 1: I am at depth... maybe 70' ... my buddy is swimming off to photograph a turtle maybe 20' from me and I take a breath and for whatever reason I've got nothing. Panic! Can I swim to my buddy and grab their octopus? What if my buddy is swimming with the turtle and away from me? Can I close the gap? Can I signal my buddy to stop and swim towards them at the same time? I don't really know the answers to these questions. In such a scenario, having 10 good breaths would be a potential life saver. (That's about what I get from Spare Air 300 at 100'). I'm not looking to make a safe ascent from the bottom with a safety stop on Spare Air. I'm just looking for the nearest person with a functioning regulator. In the situations where I am diving (always with a buddy or a group, but often with strangers) this makes sense to me. After reaching my buddy we ascend together at a leisurely pace, making a safety stop and all is well.

    Scenario 2: Again I am at depth of 70' and I experience an OOA emergency. This time my buddy is in full pursuit of that turtle and I don't think I can catch them, even with the few extra breaths of my Spare Air. I almost always dive NDL, so I'm going to make an ascent from depth with my Spare Air. I'm in an emergency so I'm not going to go with a conservative ascent. I'll ascend at perhaps 60 feet per minute and if there's any air by the time I'm near the surface I'll slow the ascent a bit but not make a safety stop. I'm perfectly willing to take the modest risk of the bends over the certainty of asphyxiation. I've tested my Spare Air 300 a few times making ascents while breathing from it and I can make it from 70' to 15' with several breaths left in a modestly paced ascent.

    Scenario 3: I'm diving with my buddy at maybe 40' depth. My buddy is really close to me but he's not looking directly at me at the moment I have an OOA emergency. Without Spare Air, what do you do? Swim to your buddy, tap them, wait for them to see you, make the out of air signal and proceed to wait for him to give you his octopus or long hose or whatever? Maybe, but I suspect that is not how it would go down. I am told in almost all real-world cases the diver OOA tackles the buddy and rips the regulator from their mouth. This in turn can send the buddy into panic. Perhaps I've got a novice buddy using rental equipment and they can't even find their octopus. They choke on some seawater and... well... things go badly. With Spare Air, I have an immediate backup to go to first and then I can get my buddy's attention and arrange for an orderly sharing of their air to make a leisurely ascent to the surface.

    Are these scenarios realistic? I know these situations represent only a fraction of what could go wrong underwater. But I think they are at least plausible scenarios and if there is a tool that can assist in these scenarios... I feel slightly better for having it with me.

    The typical posting I've read against the use of Spare Air usually states that having a 13 or 19 cubic foot pony tank would be preferable in almost all situations. And indeed more air would be better. However I am usually travelling by air to my destinations, and two factors make carrying a larger pony bottle prohibitive: First, airline weight limitations and secondly the TSA requirement that scuba tanks be disassembled with valves removed before travel. The Spare Air is lightweight and it's very easy to unscrew the regulator section by hand before flight, secure in a see-through plastic bag and reassemble at my destination. The fact that it's fairly small, lightweight, easy to fill, and doesn't add a lot more clutter to my setup, are all positives that mean I likely use it more regularly than I would a pony tank.

    So those are my thoughts on the subject. I hope I never have to use a Spare Air except in testing them, but it is somewhat reassuring to me when diving in a new location with new people to tap my side and reassure myself that it's there should I need it. Please note that my experiments using Spare Air are just my personal experience in a variety of different environments and depths. Your mileage may vary.

    :)
     
    BDSC, Saboteur, peterak and 3 others like this.
  4. scubadada

    scubadada Diver Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Philadelphia and Boynton Beach
    9,832
    5,178
    113
    It's not difficult flying with a 19 cf pony, I've never had a problem, checked or carry on.
     
    markmud likes this.
  5. Will_A

    Will_A Angel Fish

    # of Dives: 50 - 99
    Location: Los Angeles, CA
    9
    17
    3
    Do you unscrew the valve and leave it open to inspection? I'm sort of timid about doing this with a "real" scuba tank. When I travel, my Dive Bag frequently gets that secondary TSA inspected note left in it. I assume (without any evidence) they saw the tank and were checking it.
     
  6. scubadada

    scubadada Diver Staff Member ScubaBoard Supporter

    # of Dives: 1,000 - 2,499
    Location: Philadelphia and Boynton Beach
    9,832
    5,178
    113
    Absolutely, that is the rule. I put a loose cap on the tank with a note that says, "remove for inspection"
     
  7. tomfcrist

    tomfcrist NAUI Instructor

    # of Dives: I'm a Fish!
    Location: Virginia, USA
    2,861
    1,747
    113
    34A5CACF-79E6-4A35-9ACA-FCCBCD011ECE.jpeg
    Heeds bottle. When I was working SAR in Key West, we had 6 cuft bottles wit Zeagle regs and a hose....way better
     
  8. wetb4igetinthewater

    wetb4igetinthewater Instructor, Scuba

    # of Dives: 200 - 499
    Location: Seattle
    2,994
    1,366
    113
    Simulations are nothing like an actual emergency. Your adrenaline is going to kick in. Adrenaline causes respiration to increase. How much it goes up varies. You may want to read some of the references in the attached file.

    For 30 feet or less, I wouldn't bother. I'd just do a CESA. Depending on how full your tank is, you have a variable number of seconds before your cylinder is empty.

    Edit: for travel, you don't have to bring a pony. You could sling another cylinder (just bring a reg and sling), or dive sidemount. Your call depending on if you become oblivious to the world like me when taking pictures.
     

    Attached Files:

  9. BurhanMuntasser

    BurhanMuntasser Dive Charter

    # of Dives: I'm a Fish!
    Location: Nomad
    5,267
    1,587
    113
    I have to think why I ran out of air underwater before anything else. In my environment, the biggest hazard for me after dynamite fishing is getting caught on fishing lines, nets, debris or anything that would impede my ability to ascend to the surface on time before I am able to cut myself out of the entanglement. I have to have enough air not to get back to the surface but to be able to cut my self out of the entanglement and then make my ascent. Spare air isn't going to cut it at all especially when considering the "excitement" and dramatic increase in breathing rate. 30cuft is minimum for me but it depends on depth and various other factors. I do it with a 40cuft or an 80.
     
    certainmisuse likes this.
  10. markmud

    markmud Self Reliant Diver, On All Dives. ScubaBoard Supporter

    # of Dives: 200 - 499
    Location: South Lebanon, Ohio
    987
    799
    93
    Hi Will,

    I uncork it and leave the tank wide open. FOD is easily detected and cleaned out; use your dive light and look inside. My ponies have been travelling on airliners for more than a decade. I get the TSA note about 1/3 the time.

    cheers,
    m
     
    Compressor likes this.

Share This Page