tech_diver's Final Report on the Hydroid Aquabreather
Introduction
Every new advance in diving has met resistance and skepticism. Even submersible pressure gauges were first derided as dangerous single point failures that real divers didn't need. I've always told myself to keep a scientific open mind because I didn't want to be one of those crusty old guys that poo-poos what will turn out to be the way of tomorrow. I want to believe in the next big thing as much as anyone but the Hydroid Aquabreater is not it. It is a fake.
There are specific physical limitations to the size and configuration of a rebreather primarily centered around the counter lung. The volume of a counter lung is contingent upon the physical size of the diver and the nature of the diver workload. They range in volume from 4 litres (very, very small diver) to 8 litres. The Hydroid people claim they use a 6 liter counterlung.
The smallest rebreather I've ever seen in my decades in the business was the 'Eoba' from Japan. Two small cartridges in the mouth piece supplied oxygen and a small scrubber canister was worn on the back of the neck. The corrugated loop hoses were the actual counter lung and they would stretch up and down to many times their relaxed size like tentacles as the diver would breath. Even this small design could hold only a few liters of exhaled gas but it would not roll up to fit in the Hydroid helmet.
It is very obvious that there is no room for a 6 liter counterlung in the Aquabreather helmet. Especially when you consider that it is said to also house a small diluent tank, two beer can size scrubbers, computer modules, sensors and a battery pack. Imagine holding the helmet upside down like a salad bowl, putting a human head, a Spare Air, two beer cans and then pour three 2 liter jugs of soda pop it.
Typically, counterlungs are mounted on the chest, back or over the shoulders and are positioned carefully to minimize the work of breathing. I'll leave it to rebreather divers to discuss the adverse effects of having a six liter counterlung mounted on your head.
They claim that the scrubber canister also contains potassium hydroxide which gives off oxygen while removing CO2, however they would not tell me the ratio of sorb to potassium claiming it to be a trade secret. This makes it impossible for me to calculate how much O2 this thing will generate so we can't really know what the duration of their scrubber is. They claim that it will last for an hour down to 42 meters but I find that highly dubious for sixteen ounces of sorb.
During the demo dive, I noticed the diver's breathing to seem shallow. As an instructor, I would have noticed it on a student if they weren't breathing fully and comfortably. This unit is not a fully computerized rebreather that generates is own O2. It became obvious what they had done.
They said there is a 95 liter tank of breathing gas in the helmet for diluent and bailout. 95 liters is 3.2 cubic feet. If 3.2 cubic feet sounds familiar, it's the volume in a Spare Air tank. They have a Spare Air leaking air into the helmet airspace and the 'diver' is breathing through a 'CO2 Rescue Mask."
Personal CO2 Scrubbers - Naval Technology
Comex Emergency Respiratory Unit (ERU) for Lung Powered Carbon Dioxide (CO2) Scrubber ER-216-000
The stunt would not be hard to duplicate with a bucket. You put on the CO2 rescue mask, put the bucket over your head then walk into the water. Then you stick a leaking Spare Air up under the bucket and you are in business. You could even decorate the helmet with the face of a mermaid or zany dugong.
Currently, we have been told that they have one working unit yet they are telling people that it will be available for retail next year for about $4000. This will never happen. I have seen lots of underwater products and you don't go from one functioning unit to retail in a year. If I showed a high end dive computer that had one shaky prototype and claimed that I would have it on the shelf in dive stores within a year, everyone would laugh at me. I don't know why anyone would believe that about a radically new computerized rebreather. It didn't help his cause when he claimed the tank could be refilled by a bicycle pump or 12 volt compressor.
In our industry, we do have meetings with designers who have bold new ideas for equipment. However, in those meetings, critical design questions are answered. In talking to the Hydroid people, several key pieces of information that could validate their claims were being withheld under the guise of 'secrecy.' In the real world, we discuss those specific elements that make a new product possible.
We have a series of case studies for 'technoscams' on crowdfunding websites. One example is the
Triton artificial gill but there are other much larger cases. In one case, a designer claimed to develop an electronic device that you wave over your dinner plate and it reads out all the carbs and calories. While people fall for these things all the time, there are several red flags associated with these vaporware techno scams.
- Slick prototypes that look like movie props
- Withholding key pieces of critical information that make the product possible
- The product's existence requires several simultaneous technological breakthroughs in disparate sciences
While I do believe the entire demo was faked, I do keep an open scientific mind open to new evidence. If they or anyone out there can put a functioning product like this on my desk, I have access to an worldwide distribution network that reaches from navies and NASA to spearfishermen and vacation divers in the Caribbean.
This rebreather was just a bucket with a CO2 mask and a Spare Air in it. If the guy's head exploded in a violent potassium reaction, it would have lent some credibility to their claims that they actually had some form of regenerative rebreather. That would have impressed me. Maybe next time...
