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Broke even CCR vs OC fills costs!

Discussion in 'Technical Diving Specialties' started by northernone, Aug 16, 2017.

  1. jadairiii

    jadairiii Solo Diver

    Would love to know what boat you have to get that number. In South Florida, a single dive trip is what it would cost in fuel alone, if I still had a boat.
  2. Doc Ben

    Doc Ben Angel Fish

    # of Dives: 1,000 - 2,499
    Location: somewhere diving
    Really? Welding gas? Is that smart? What are the specs on this gas?

    It seems this whole thread doesn't take into account the increased risk that CCR diving has, compared to OC. What is a life worth?
  3. Superlyte27

    Superlyte27 Cave Instructor

    # of Dives: 5,000 - ∞
    Location: Florida
    I did this back when I first got a rebreather. I just did the math again... It costs me about $6/hour to dive a CCR, pretty much regardless of depth. Here's my numbers... You can do the math...please correct me if I'm wrong. I did this while watching a movie with the wife and kids, patiently awaiting a hurricane.

    First, the retail cost of several popular rebreathers including instruction is about $9500.

    I used 300 hours, as that's the most diving I did when I was very active doing a lot of 300' dives
    Sorb costs me $115 per keg. A keg of sorb weighs 45lbs (especially if you weigh the kegs at the shop and pick the heaviest ones, they fluctuate by as much as 5lbs) Assume you'll get about an hour per pound. My two rebreathers hold just under 6lbs and are good for about 6 hours without pushing it. So 45hours per keg requires 6.66 kegs @ $115/keg is $767.

    I also on a bad year buy 4 oxygen sensors. Retail is about $80/sensor. Thankfully, I don't pay retail. But we'll use that number. So $280 annually on sensors.
    I used to spend a fortune on mushroom valves for the rEvo. Thankfully, my current rebreathers have good mushroom valves. So on a bad year, I might spend $20 on mushroom valves (retail) but I haven't replaced a mushroom valve in two years and I don't pay retail. But assume I'll have a bad year eventually.

    If you rebuild your first stage regulators annually (I don't rebuild until IP creeps) then plan on $25 in parts, and $30 in labor. I rebuild my own, and I don't pay retail for parts.
    Also, you can plan on replacing o-rings as needed, or during an annual service. That's up to you. I replace as needed, but an annual services would remove the above cost and replace it with $250 annually for new orings, hoses, mushroom valves and 1st stage rebuilds, etc. Let's use that number for easy math.

    Now, this is where it will get a bit tricky...
    I don't pay for gas fills because I'm affiliated with a few shops and a few shops are just really good to me, but my students do. They're charged $6 for a minimum fill of O2 or Trimix. Let's plan on all 300' dives. My rebreather has 4liter bottles. 4 liters at 200 bar is 800. 800 / 1 liter per minute (what a male person consumes on average at any depth in oxygen) is 13 hours. And frankly, a good rebreather diver will consume even less diluent, and typically, diluent bottles are filled to a much higher pressure than 200bar. But we'll use 13 hours for this math. Because I have big bottles and a lot of time on CCR, I might dive all week on a single fill of O2 and Dil. We're trying to get the cost for 300 hours on the loop. If we just assumed 10 hours per fill (and frankly, we exceed this often) we're looking at 30 fills at $12. $360 in Gas fills for the rebreather. I'm not going to add in bailout, because frankly, it's not consumed unless you need it, and if you need it, I'm pretty sure you're okay replenishing it, since it likely saved your life.

    So what's the math? $767+$280+$250+$360 = $1657/300hours = $5.52/hour. And here's the kicker... want to go to 400'? That cost doesn't change significantly.

    Well, what would 300 hours at 300' cost on OC? I haven't given it much thought... But let's see if I can figure it out.
    Plan on a .5 SAC.
    300' / 33 +1 = 10ata x .5 = 5cu' per minute. But, I'd guess than only 25% of that dive is actually on bottom mix. The majority of that dive is deco gas. So 300 hours x 60(minutes) x 5cu'/min x .25 = 22,500cu'.

    Now, I haven't added up the cost of Deco gases like Oxygen and 50%. They are not insignificant. But if you take EE's cost of $.67/cu' for 10/70, you'll see that 22,500cu' for 300 hours of diving at Eagle's Nest will cost you about $15,075. Of course this is assuming all 300' dives. What if we were talking about 300 hours at Ginnie? Well, let's see... We replace 10ata with 4ata and we get 4ata x .5 = 2cu' per minute, except that all of that dive is on 32%. 300hours x 60(minutes) x 2cu'/min = 36000cu' x $.11/cu = $3960. Don't forget to add in annual service, o-rings, etc.

    So, I guess break even really depends on where you are diving. Diving shallow? CCR is 3x cheaper than OC. Diving deep? CCR is 20x cheaper than diving OC.
    rjack321, shoredivr, Brandon and 2 others like this.
  4. Superlyte27

    Superlyte27 Cave Instructor

    # of Dives: 5,000 - ∞
    Location: Florida
    The increased risk of CCR diving? IMO CCR diving reduces risk... here's why.

    Let's pretend you're 4000' in the back of a cave. You've lost your buddy, lost your line, lost your lights, lost your fin, lost your way, got tangled in the line, had a scooter die, had a cave collapse, had an entrance blocked by a boulder (like at Peacock a few years ago), etc... On OC you have a very finite amount of time to resolve any of these. Depending on the stage of the dive, you could have had as little as a third of your starting pressure to resolve any of the problems above. But on CCR it's possible to have 10+ hours to resolve all of those issues. Lost a buddy? No problem, I can take 5 hours to find him. Cave collapsed? I got time to start digging. I got lost, time to find myself. Trapped in a line, time. TIME TIME TIME TIME TIME....

    A ccr provides resolution (through time) for 20 different issues. In doing so, it adds just three possible issues: Too much Oxygen, too little Oxygen, or too much CO2. I'll take those odds every time.
  5. sunnyboy

    sunnyboy Instructor, Scuba

    # of Dives: 500 - 999
    Location: Vancouver Island, Canada
    There was a post many years ago now from a diver who got lost in a silted out room in a wreck. As he was on a rebreather, he was able to calmly wait until the silt subsided enough that he could see the way out and survived. That was a very powerful story to me.

    The problem with rebreathers IMO comes down to one of inexperience or complacency. One or other is almost almost always implicated in RB fatalities.
    Dark Wolf and northernone like this.
  6. tomfcrist

    tomfcrist NAUI Instructor

    # of Dives: I'm a Fish!
    Location: Virginia, USA
    Are we really going to get into this? Ok, I'll play. I own my own bottles...they don't get used for welding. There is zero chance of backflow of acetylene, argon or any other thing in my bottles. The dudes that fill my tanks...do it while I wait...and fill it from the same source that they fill all the other "high purity" gasses from. They just charge less because they don't have the liability of claiming it is 3 9's pure.

    Industrial gasses have been used in Trimix diving for....as long as we have been using Trimix. OC or CCR, doesn't mean ****. Trimix is Trimix.

    Now if I was unhooking my O2 bottle from my cutting torch and filling, maybe there's a chance of contaminated gas.
    rjack321, Brandon and northernone like this.
  7. ajduplessis

    ajduplessis Solo Diver

    # of Dives: I'm a Fish!
    Location: dry land :-(

    I thought a scrubber only have 3-5 hours life but you will do 10 hours... Also once you have extended your stay on a CCR will your bailout also magically increase to cater for the new 5-10hour additional time? The accelerated bailout profile used by CCR divers to exit is generally aggresive and dont cater for any delays getting to the surface.
    PfcAJ likes this.
  8. KevinNM

    KevinNM DIR Practitioner

  9. lermontov

    lermontov Manta Ray

    # of Dives: 500 - 999
    Location: christchurch
    consider other factors such as if you've already got your thousands of dollars worth of OC gear then switching to CCR and all training to go with it.
    How often do you miss dives on CCR due to issues as compared to OC missing dives -thats a cost if your half way through your trip.
  10. Patoux01

    Patoux01 Solo Diver

    # of Dives: 100 - 199
    Location: Geneva
    "You can't break even a ccr" is what I've been told by the rebreather salesman I've had a long, hard chat with....

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