As a matter of fact this is a kind of "gray" story. For a long time nobody paid it any serious attention to it for two main reasons:
It was a military mission and any attempt to find anything interesting about it could be easily prevented because of the secrecy surrounding the events:
It was just a plain unsuccessful flight that failed to dock with the station.
If it were not for the extraordinary events that occurred by landing on the lake, it might have been totally unremarkable. But it is remarkable!
Here's what really happened:
The Preparation for the mission was standard, like all others; with only one exception the real program of the mission was a military one, which required special additional training.
The Crew was special also they were both from a special cosmonaut's team selected specifically for Almaz (military) missions. That's why their training was mostly conducted at Star City (secret facility which belongs to the Air Force) and NPO Mash (designer of Almaz) and much less at NPO "Energiya" (designer of Soyuz spacecraft). Because of they were military specialists, the crew knew much more about the program of the mission and the Almaz station than about spacecraft.
Sure, they passed all the necessary procedures and exams but there was the human factor...
The Launch and approach to the Station was standard, nothing unusual. Everything was OK until the last minute of the docking, when Mission Control noticed a difference between reality and the data being sent from the spacecraft's devices. The spacecraft was approaching the station too fast, and with the wrong orientation.
The approach (which was automatic) was canceled by Mission Control at a distance of 40 meters from the station and the crew awaited a command. They were now in the shadow while standard procedure presumes and requires docking in the Suns light.
When they came back into the "lighted" orbit the crew got a command from Mission Control to be ready for preliminary landing. A request of the commander (Zudov) to override the automatic docking in favor of a manual docking was rejected. Why?
There were several cases of similar unsuccessful dockings (1969 Soyuz-7 and Soyuz-8, 1974 Soyuz-15, and later 1977 Soyuz-25 and last one case 1983 Soyuz-T-8). These all happened because of errors in the docking device "Igla" ("Needle"). When there was an experienced commander on the spacecraft he was allowed to do a manual docking. A commander on a first mission would never be allowed. This happened in our case. Both members of the crew were first (and last!) timer's in Space.
During The descent Process, the spacecraft engines were used too little, but this was not unusual or wrong, the commands were given by Mission Control. It resulted, however in a deviation from the standard landing area this happened because of a mistake in the calculations of Mission Control.
Landing mistake in engine thrust and an error in the targeted landing area by Mission Control there were some additional influences but by chance from the weather. It was very windy and that's why the capsule deviated even more approximately 150 kilometers from the proper and expected landing place.
Water landing on frozen lake Tengiz.
The Cosmonauts were acting according to standard procedure and did not jettison the parachute after the landing. BUT the situation they were in was not standard (and not foreseen in the landing manual or training for an all water landing). They landed on a frozen lake and broke through the ice! The parachute got wet and its weight pulled the capsule upside down! As a result not was the only evacuation hatch under water, but a special valve for connection to the outside atmosphere to get breathing air, was now also under water! The valve was already open which was standard procedure at the altitude of 5 kilometers. When the capsule turned upside down water started to go through the valve the capsule was sinking so the cosmonauts closed it with something. Sealed in the capsule, half underwater and upside down, they were now breathing regenerated air. Time was passing, and the danger of suffocation increased because the regeneration system was losing its power quickly as it was not designed for 12 hours of work.
Cosmonaut Zudov's Own Words:
"...We had no possibility to get out of the capsule, as we did it before and as we were taught. If we open the hatch, and it was under water, the stream will come onto the cosmonauts, and there would be no chance to get out. Besides very low temperature on water. Temperature on Lake Tengiz was minus 22 (C). To stay in such situation in the spacesuits and do nothing we would be frozen and die. That's why first we had to do to get out of spacesuits and to free ourselves of them. We spent and hour and a half to get out, even used knives to cut them. Then we managed to wear our plain sport wear. Started to save electric power. Switched off all sources inside the capsule left only radio beacon and radio station which we could use in due time but it failed soon...
...Our work inside the capsule was, as it seems to me, more clearly to my mission engineer at least he was a diver, submariner..."
Cosmonaut Rozhdestvensky was in the Marine Air Force special divers unit, not on a submarine! But he devised a strategy to conserve the precious and life sustaining electricity for the air rebreathing equipment.
"...You could feel CO2 (carbon dioxide gas) without any instrumentation, just feel it.
When I felt that it at the stage which we could loose consciousness then I switched on the regeneration unit. Then, when the mind started to clear, and blue halo we were starting to see disappeared in the eyes I switched it off. And so on all the night."
Helicopters could do nothing there. In the frozen blowing mist, which covered all the lake helicopters could not go down. The crew was in trapped like in a can...
Divers also could do nothing in that salted quagmire. All efforts to put a plate under the capsule or turn it around failed. That's why, finally, there was an order to hook the capsule over the parachute and drag it to the shore by helicopter. They did it and dragged the spacecraft for around 5-7 kilometers.
"...When I got to see our photos and how they dragged the capsule then I really was frightened the only time in my life I was really frightened."