Diver Daves' IDA-76 Page

OK, guys and girls. Here's a real stumper. It's a very neat little chest-worn 02 rig that my buddies sent me, and I have no clue what it was used for. I'm not sure if it was for intentional diving, or for escape use, or ? . In any case, it's a cool little rig, and it's presently the subject of a project to turn it into a trimix bailout rebreather. So, without further delay, let's rip 'er apart!

Here's the rig on the bench, laying out flat for inspection. The 'round the neck counterlung is visible, as is the DSV and hoses. The adjustable overpressure valve is at the lower right side of the counterlung when worn, and the emergency inflation wings are folded in and stowed.

Here I have unfolded the emergency inflation wings, and have opened up the front flap to expose the guts of the rig. The front flap has been unbuckled and rolled up, and you can see the strap holding the scrubber into the chassis is still fastened.

The counterlung is made of a very durable rubberized cloth, much like that used on older Scubapro BC's. Here you can see the auto/manual add valve which is located at the nape of the divers neck. The purge button may be manually depressed, as in all Russian rebreathers, for manual bypass, or the counterlung may be collapsed by breathing and the automatic function of this valve will automatically add gas upon demand. The DSV is the typical brass Russian one used on all of their rebreathers, and depicted in detail in the AKA-60 and IDA-67 teardowns.

The exhaust valve is of chrome plated brass construction, and is adjustable for relief pressure. This allows the counterlung volume to be controlled as per the divers wishes.

Now I've opened up the flaps that protect the scrubber. You can see the curved contour of the scrubber, giving the rig a very low profile. But where is the 02 bottle? Just wait and see!

There is a flip-lever for opening up the 02 supply, so there are 02 bottles hiding in here someplace. The overpressure relief valve is visible here, as is the toggle to open up the 02 to the addition valve.

Not only is there a flip-valve for 02, there is also a pressure gauge. See it peeking out of it's protective ears? Hey, what are all of those C02 bottles doing in there anyway?

Ye-Gads, Man! Those aren't C02 bottles! They are the worlds smallest cascade system! A series of small high-pressure bottles are connected to each other to provide a supply of oxygen. How clever. The rig has been designed from the inside-out to be as tiny and as compact as possible, while still using gaseous 02 as the breathing source. Here the scrubber has been removed and the cylinders on either side of the chassis exposed to view.

Here I've lifted the entire bottle rack and scrubber out for inspection. But wait: There's more! The two bottles on the right are independent inflation bottles to provide a source of air to the emergency inflation wings. They are a totally isolated system from the 'main' 02 bottles.

Here's the scrubber, and as you can see it's very neatly curved to fit the divers chest contour. The rubber boot at left covers it for thermal insulation. I guess they planned to use these in cold water, Comrade!

Here's what's left of the chassis when the scrubber is removed. You can see the 02 bottles, the emergency inflation bottles, the valve with flip-lever, and the gauge assembly. The breathing hoses of the loop are attached to the scrubber through the holes in the top.

With the chassis removed, the secrets of the flexible components are revealed. The counterlung is attached at the top of an 'apron' of the same rubberized material, to which the chassis is attached by tabs and loops. The emergency inflation bladders bracket the area where the chassis will be reinstalled. The inflation cylinders are shown connected to the 'T' hose that feeds both of the bladders. It would be a 15 second scissor-job to remove the inflation bladders if desired.

That's it for this tiny 02 rebreather. I'm still baffled as to what it was designed to do. I do know, however, what I'm going to do with it. I'm going to cut off the bladders, add a pair of drysuit valves, and hook one to the air-bottle on the ass of my Mark-15 and the other to a real 02 source. The rig will act as a bailout rebreather with minimal work, and the existing tiny 02 bottles (capacity unknown, but probably about 1 liter) can act as a tertiary 02 source. It would be easy enough to use it as a constant volume deco rebreather without any electronics, but I'll probably install a LED Heads-Up display on the DSV. If anyone has comments on this, I'd sure like to hear from them.