Diveman underwater breather

[Rich Keller]

How long is the hose coming from the surface? How many cubic feet is the bag? How exactly is the bag being filled? I see the straps attached to the bottom of the bag but I do not see any bellows.

 

[elmer fudd]

As far as I can tell, here's how it works. On the surface you have an inflatable beach ball thingy with the hose sticking up through it. The hose itself is 20' long and attaches to the oval cylinder. Inside the cylinder you have an air bladder with foot straps attached to it.

You wear the cylinder on your chest and the straps go around your ankles or your instep or something. When you extend your legs it draws air into the cylinder. "Retract" your legs to inhale the air you just pulled down to depth. Repeat as necessary.

Every time I look at this I'm just struck by the number of potential failure points in it. It all looks so flimsy and half-assed.

 

[Rich Keller]

I get that there are a lot of potential failure points and I understand how the thing hooks up to your feet but what I do not see is how this thing is creating suction to bring down the air to the bag on your chest. I also have an idea from using surface supply air that a hose that long is only good for about 6' of water or less so we are talking about 2.5-3 psi over bottom pressure.

 

[Airleron]

I see some PDVs in this design.



Potential Drowning Victims



Hey, that looks like my Jet Air! Nice!

 

[elmer fudd]

As you pull that bladder out of the cylinder you create a low pressure area inside the cylinder that should suck air down from the surface. Basically, the cylinder starts out filled with a water filled bag. As you draw the bag out of the cylinder, air is pulled down from the surface to replace the displaced water. There would have to be a mushroom valve on the input and output of the cylinder as well to prevent the air from flowing back up to the surface and also to prevent it from sucking the breath from your lungs.

After the air is pulled into the cylinder, it appears to me that it would be at the same pressure as on the surface, until you released the tension on the foot straps, at which point the air would compress to the ambient pressure and it's volume would decrease proportionately.

I'll take your word for the depth limitations of this. The Craigslist ad says you can go as deep as 20' and it sounds like he just lifted the ad copy from the packaging.

 

[scubasteve65]

There is one up on ebay now. $100 delivered. I used this thing before it went to market here in the USA. A buddy of mine worked for a Japanese import/export co in NYC and they were deciding on whether or not to finance this thing. It works, but you better be coordinated. I was only in a 12' pool but you can stay down indefinitely. You can swim with a flutter kick until you've used up the air in the bladder. At that point you bring both heels to your a$$ and then extend them straight again, drawing down more surface air to fill the bladder, and return to your normal flutter kick. It's like a hookah rig without the compressor. I could see having a blast on a shallow reef in clear waters. Definitely not for uncoordinated folks. In reality, you're talking about a 15' free swimming ascent worst case scenario.

 

[Sitkadiver]

Looks like a fun pool toy. My kids would love that.

 

[Couv]

I'd try it in a pool. I've always wondered if some sort of u/w bellows with check valves in the right places would be a fun science project.