$100 Hot Water Bottle Pendulum Rebreather


Humans exhale a lot of oxygen along with their waste carbon dioxide. Instead of throwing out this oxygen, a rebreather uses a scrubber to remove the CO2 and replace it with pure oxygen from a bottle. Tom Rose built this rebreather for $100. When you exhale air passes through the scrubbing material and is stored in hot water bottle counterlung until you inhale. The system is only 15 pounds; a great savings compared to most dive equipment. You are definitely putting your life in your own hands so this should not be used without plenty of “couch-diving” tests. Tom has a ton of other diving related projects on his site.

[via Divester]

23 thoughts on “$100 Hot Water Bottle Pendulum Rebreather

  1. This rebreather is pretty cool. I am sure it works, but I wouldn’t use it.

    One of the problems with this system is that the diver could either get too little, or too much oxygen. Too little and the diver would pass out and probably drown. Too much and the diver could die from oxygen toxicity. Pure oxygen below 20feet will cause oxygen toxicity and death.

    If anyone is tempted to try this they should do their homework first. They need to understand the dangers of scuba diving and why oxygen can be toxic.

    Diving is great fun. It is a good sport for geeks. There is the technical aspect of all the gear. And there is a great opportunity for discovery as you never know what you will find.

  2. There are some pieces of gear which I will pay good money for because they have been deemed safe by experts. For example: SCUBA gear, Parashoots, Firearms, Babyseats, Ejection Seats, and Microwave Ovens.

    I do not recommend “hacking” together any of the above. In the event that you do, please video tape it for us to witness.

  3. now we can all pitch in to h-a-d’s legal defense fund! because somebody stupid will drown, and then the stupid parents of the stupid kid will sue. because we put a gun to his stupidhead and made him do it.

    hacking safety gear isn’t safe. if you do it, you are the reason safety gear has so many warnings.

    first hack-bash. not proud of it.

  4. The usgov’t believes that rebreathers could allow a diver to be undetected underwater for long periods of time and I’ve been told by dive store owners that the FBI keeps track of people who buy rebreathers and takes a special interest when they are stolen from a shop. If this one minimizes bubbles and maximizes time like a commercial version, it would make it harder for the FBI to track down who has one.

    CNN reported back in 2002: “Since September 11, FBI investigators asked dive training industry officials for the names of all people who had been trained in the use of sophisticated “rebreathers,” one industry official said.

    Unlike recreational scuba gear, the closed circuit rebreathers and semi-closed rebreathers produce very few or no bubbles, and some do not have magnetic signatures.”

    Search for “rebreather” in this article for the context:


  5. @9

    While that’s all well and good. It honestly is a lot of media hype. Yes, it can be an issue. But this is not new technology. Anyone with an internet connection or a library card can find out how it was done during the primitive ages of rebreathing and the advancements in WW2+.

    That being said, you can buy a “safe” system off eBay for under $1000 – you could even run Nitrox if you want… Using a rebreather does not make you a non-rec diver either – I just thought that was misleading from the article :P

  6. Geez, Im glad the creative minds that pioneered the innovations that have changed our lives over the centuries werent as much of a pussy as you guys. While its true that his design has an inherent risk factor due to the fluctuations of various toxin levels, these levels can be real time biometricly monitered extremely precisely, with the very real viability of devices and/or processors within the apparatus to take constant bio-readings and make the necessary chem/gas adjustment to safely continue. All it takes is enough R&D and above water testing to be reliable. And at the very least have an alarm system, with another backup alarm system, to alert the diver to improper conditions so he can immediately surface. After all this system wasnt intended for deep submergence anyway.
    And even the author is making a heads up display to keep him updated to variables while hes under. or did you even read that far?
    one of the thing that makes this risky is that people may try to assemble a device with just whats in his description. in case you didnt notice he has left out and kept secret some important details to make this thing functional. that coupled with some scare propaganda to keep people from trying and figuring out the full plan because he knows that if people know his full design they could then go on to improve upon it faster and better than he ever could.
    *although to his credit im sure hes also got peoples safety in mind too*
    i agree that safety is important, but dont forget the fact that you could test indefinitely on dry land where the proper lifegiving air is only a masks pull away. for that matter, who says this would only be for aquatic use? firemen could shed many pounds of breathing equipment and be more effective in saving lives, in that last big coal mine accident, the rescue workers were afraid to go deep enough into the tunnel to rescue all those oxygen deprived workers due to the unsafe air. if they had these they could have promptly pushed ahead and no doubt saved some, most, or maybe even all of them. also possible emergency aircraft water-crash devices. you couldnt hang a shitload of scuba rigs around the aircraft but you could certainly outfit it with these compact lightweight lifesavers.

    thats not even going into the enormous military applications. the seals and sf use a heavy large cumbersome device called a draeger.
    if they had a 10 to 15 pound rebreathing rig then they could carry alot more other gear, not to mention the fact that it could be extremely covert. possibly concealable under a suit, or carried on an operators body along with his other regular dry-land assault gear. yes the possibilities for this tech are very awe inspiring indeed. one could escape from any persuers just by finding the nearest body of water. a real life aquaman.

    even though foreign intelligence services and our own uber-top secret weapons grade research facilities are no doubt all over this and have
    probably even perfected it by now, their *hacks*, although years and years ahead of us mere mortals in conventionally funded r&d labs,
    are and will remain highly classified. so, the first private individual or firm who perfects and patents this lightweight rebreather could potentially become *billionaires*.

  7. hey david (#10), #9 rob carlson says that “I’ve been told by dive store owners that the FBI keeps track of people who buy rebreathers and takes a special interest when they are stolen from a shop” … sounds like the first indiviual to patent this did it awhile back. Apparently there is a reason that it is not so useful in emergency situations. Firemen and other rescue workers probably prefer tanks of air due to the fact that the victims of whatever accident most likely need air too. this also sounds like a great diy escape tool, but i’m sure the draeger is worth its weight in gold if the seals are using it over rebreathers.

  8. Rebreathers have many other applications and uses, beyond scuba diving. As pointed out by someone else, fire-fighting is one of them. Hazardous waste sites, underground utility work, and confined space entry programs are other applications. These applications often require an second breathing option (typically an escape bottle) and a rebreather makes a good option. And yes, as pointed out by someone else, oxygen concentrations are safe within only a fairly narrow range of 19.5 to 23.5% of the air. Concentrations higher and lower than that range can cause dizziness, unconciousness, and toxicity. However, there is no reason to believe that a rebreather can’t be fitted with a regulator.

    I don’t for a second believe that nonsense about the FBI tracking you if you have a rebreather – lack of bubbles or not, it is pretty easy to be undetected when diving underwater. If that is the cleverest idea the FBI has come up with to “protect” us, we are in for big trouble. Given that the article you cited is 4 years old, I would say it is more a result of the hysteria following 9/11, than any really sound plan for tracking suspicious activities.

  9. As has been pointed out in the comments, this can be extremely dangerous. If you must do it, spend a little more money and get a little more safety by googling the FEOR Light or the FEOR Light with Heads Down Display – both of these have electronic PPO2 monitoring, so you at least know your PPO2.

    There are hundreds of other rebreather designs on the net. Most of them are safer than this one. None of the are safer than open circuit SCUBA.

  10. It would be nice if all those miners in West Virginia had rebreathers.A rebreather combined with an oxygen tank can last for days. Unfortunately commercial rebreathers are very expensive – however, I’m sure the mine owners are going to find out that they would have been less expensive than the millions they’re going to be sued for by the miners’ families.

  11. #13 (kellen), pay attention.
    The commercial rebreathers have of course, been invented and patented. These currrent units are very large and weigh between 50 and 60 pounds! This guy is trying to perfect a very small compact unit that weighs 10 to 15 pounds, or maybe even less with high tech composite materials. also, special ops divers primarily use air tank rigs. but they will sometimes use rebreathers when they need to be very quiet, very sneaky, and for a long period of time. their milspec draegers actually weigh even more than a dive shop model. but it is a dedicated dive unit and the user is very limited to what else he can carry and how effective he would be on dry land running around with one on his back. not that its worth its weight in gold, but its currently the standard. with a very small, lightweight model like this one, possibly every man on the team could carry one on a land mission, and then be totally amphibious at only a moments notice should the need arise. i believe thats what #12 was trying to point out towards the end of that giant term paper on rebreathers.

  12. At no time do firefighters let victims use their airpacks. The #1 rule in Fire School was to never, ever take off your mask. Even if you run out of air. If you were to breath in super-heated air from the fire, it would melt your lungs and you would be of no use to anyone. I doubt we will ever see them used for firefighting applications, because carrying around a bottle of pure o2 is like carrying a bomb. The tanks that are used are filled with air, not o2.

  13. One of the reasons that rebreathers are dangerous is not just the problem of O2 toxicity. If you are not scrubbing well enough, you can also have CO2 toxicity. During strenuous exercise (rescuing someone from a mine perhaps?) your body makes more CO2 that it must blow off. Your brain adjusts your breathing rate so that you breathe more deeply and more often. Now, say you’re wearing a rebreather that’s not so hot at C02 scrubbing. If you breathe in high concentrations of CO2, your lungs can’t get rid of what’s in your body as efficiently(decreased diffusion gradient). Therefore you start to accumulate CO2 in your body. [C02 gets converted to HCO3- in your body by pulling an OH- molecule off of water and leaving the H+ ]. This lowers the pH of your blood. Acidic blood is very very bad, ESPECIALLY if you can’t blow off the CO2, as in a rebreather situation. Nasty cycle. Nasty death.

  14. David, Your comments on how such a system could be made “safer” are correct, but I think you misunderstand a few things:

    First, the warnings, They are given because rebreathers can *actually, really truly* be extremly dangerous, not because of some goverment conspiricy. Some of the best divers in the world have died while using (professionally designed, NOT HOMEMADE) rebreathers that were functioning correctly, don’t think that something that you cobble together in your privately funded garage will be anywhere near the safety of a commercial system. Divester usually caries stories about fatalities. Hence the warnings: You don’t want to be the next one, please don’t play with rebreathers. Also, assuming that your college Bio and Chem classes will let you figure out all the kinks in the system would be a big mistake

    Next, the uses: In addition the the problem of hauling a bottle of pure oxygen (#19 beat me to it), most rebreathers require constant attention, even when you are consuming o2 slowly (at rest), if you are subject to physical exertion, so much the worse. This is why you don’t see them replacing SCBA units in mine rescues, or handed out to folks on the street. Also, for your mass casualty uses (mine accidents, airplane accidents over water, etc.), what is usually needed is a large volume of air or pure o2, which a rebreather cannot supply.

    Lastly, the essence: What the author wanted to show is that one of the most expensive systems in diving is based on a very simple system, *which still works.* Those who are intimately familiar with these things can often make them from materials that would suprise the average consumer.

    General thoughts:
    As to the FBI tracking you, there are only two reasons to use a rebreather.
    1) to stay down for a *really* long time, and
    2) to travel underwater undetected over any distance (few bubbles).

    If the goverment is a little woried about the second, at least they are being proactive about it. Sort of like seeing a person with guest visa looking for a multi-engine jet aircraft rating, you know?

    And last of all, your quote: “Geez, Im glad the creative minds that pioneered the innovations that have changed our lives over the centuries werent as much of a pussy as you guys.”

    I might suggest that you look up the creative mind who first managed to produce fluorine gas in any substantial concentration (currently dead due to outdated lab techniques). He might enjoy some company, but no wimps, please . . .

    For the rest of us, I think the setiment is that we’ll use a professional system, whenever possible.

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