Projects > Doux de Coly 03
Survey I
Latest update: September 8, 2007
Ralph's equipment for the first survey dive.
Since the first EKPP project at the Doux de Coly, we had searched for some survey results on that cave. We could not believe that none of the many and long expeditions who pushed this cave never published a survey.
Of course there where several depth profiles available but not single survey was ever done on Europe's longest known cave. What a shame.
A call to Monsieur Constant, the mayor of the city La Cassagne (The cave actually does not belong to the city limits of Coly but to La Cassagne) finally confirmed that there is no survey available but instead that the town would be interested to get one.
M. Constant provided all available information including high resolution maps to us.
So at 18:30 on Saturday, right after the main briefing, Brus, Hervé Deschamps and Ralph Wilhelm went into the cave in order to install the decompression rope, on which the deco bottles for the dive would be installed.
Within the same dive we placed most of our decompression gases, the backup scooters and the heating tubes. So everything was in place for the first survey dive. Early next morning we met at the cave and geared up with our mono RB 80 rebreather. A final check in the pool and off we went.
Due to the low water level and the almost non-existing flow, the pool was silted out. So we had to follow a line into the cave, which presented itself with perfect visibility.
Due to the low water level and the almost non-existing flow, the pool was silted out. So we had to follow a line into the cave, which presented itself with perfect visibility. What a change from a vis of about 20 cm in the pool to 20 meter right after entering the cave.
We did our first tie off in the entrance and then hit the trigger of our scooters. Due to the curvy layout of the cave, the first survey shots where quite short. Unfortunately Brus' scooter ate some line shortly after we started, so we brought it back to the surface to check it. As the line was caught between the washers of the seal, Brus decided to stay on the surface, while Hervé and Ralph went into the cave again.
We reached the shaft, which is exactly 270 meters from the entrance after about 30 minutes. Normally it will take about 8 minutes to travel from the entrance to the shaft, but due to laying line and surveying it, it took us about triple that time. From the last point I reeled out line while scootering until the cave made a turn and it was no longer possible to lay the line straight.
At this point I looked for a placement while Hervé was getting ready to take the data. As soon as I placed the line, he noted down the distance of this shot, the azimuth and the depth of the placement into his wetnotes. The survey line we laid was knotted every 3 m / 10 ft. So Hervé counted the knots of the line I laid while scootering along, in order to measure the distance.
Hervé and Ralph in the pool. Parked scooters from other members seen on the left side.
We laid line down to 21 m in the shaft but stopped shortly in order to change gases. This standard is procedure with the RB 80: We ride shallow with a 50% oxygen trimix. We switched to our deep stages (trimix 18/60), which we placed on the deco rope the day before. The trimix 50/25, which we used on the way in was placed at 21 m in order to be used as a decompression gas on the way out.
Then we laid line down to the bottom of the shaft, where we quickly controlled our 36 m deco bottles (trimix 35/35) and picked up the backup scooter.
On we went, laying line and taking measurements.
Communication was perfect, as we communicated not only by light signals but also by voice.
Due to the mouthpiece and the hoses of the RB 80, talk is transmitted quite well. So instead of a light signal when we finished with noting down the survey data after a shot, Hervé just shouted "Let's rock and roll!" in his mouthpiece.
But this kind of communication has also some disadvantages.
When I finished the second reel at 500 meters I made a tie off and just as I wanted
to turn around to Hervé, out of nowhere a new reel was dumped on the
floor in front of me. I could hear Hervé laugh into his mouthpiece. But
I am pretty sure he heard my curses. But since this reel only had 200 meters or
70 knots of line on it, I took it anyway.
As we had now surveyed up to a distance of 730 meters from the entrance and were out of line, we turned the dive. However, we did not scooter back directly, but decided to cut out some of the old lines. I cannot understand why someone puts in a second line if the first one is in good condition. So in several places in the deep part, you can find up to four lines running in parallel.
As we had now surveyed up to a distance of 730 meters from the entrance and were out of line, we turned the dive.
Sometimes they connect, then branch out. You could clearly see, that some of these lines where laid under the heavy influence of narcosis.
So we cut out the worse ones in order to avoid dangerous situations if someone needs to follow the line on his way out in bad or no vis.
After 110 minutes of bottom time in the deep part, we reached the shaft again. Some short but important deep stops later, we reached our first decompression bottle. Leaving the scooter behind, we decoed up the shaft switching to trimix 50/25 at 21 meters. Here Hervé also placed his heating tube and I could hear his "Ooooohs" and "Aaaaahs" as he enjoyed the warmth of his heating shirt. I decided not to turn my heating on as I did not feel cold at this time. Reaching the 6 m stop I finally decided to turn it on, as I was starting to feel a little cold.
Hervé in the shallow part of the Doux de Coly.
After 30 minutes on 6 metes we left the shaft and swam towards the exit. The "deeper" passages of the shallow way were used for one of the several "air breaks".
But as air is only used for inflating air beds or lifting habitats in EKPP projects, these breaks were done on open circuit on the gas with the lowest breathable oxygen content, normally the gas left in the bottom-mix stage (trimix 18/60).
We enjoyed the slow way from the shaft to the entrance as you normally rush through it by scootering.
Reaching the pool we slowly ascended to the surface, reaching it after a dive of 5 hours and 42 minutes. Even after almost 6 hours on the loop you could not experience any fatigue of the breathing muscles or any other negative effects caused by the rebreather. After about 20 minutes in the pool, relaxing on the surface, we disassembled and cleaned our RB 80 units that worked perfectly throughout the whole dive. It was amazing to see that there was almost no moisture in the Sofnolime, as the build in water trap has done its duty.
The next day was spent with preparing for the next survey dive. Support divers brought out our scooters, heating tubes and stages and we charged everything.
On Tuesday we went of for the second survey dive. Reaching the deep pit after the shaft, Brus signaled us to stop and took out his wetnotes. He wrote down that he was feeling some wetness in his right leg, so we called the dive. No deco was done due to the short bottom time. After 90 minutes we reached the surface again. I looked to Hervé, he nodded so we turned around and just went into the cave again. A back to back dive to 60 meters with a surface interval of less than 5 minutes is something that the classic decompression theories would state as an absolute "No no", but due to the choice of the right gases, stop times and depth we did not worry about this.
Hervé back from the second dive with a lot of old green "line".
It took us 40 minutes from the door to reach the end of our survey line at 730 meters. I knotted a new reel on and off we went. As the cave layout is more straight in the deeper part, we were able to make some longer shots. The longest one was exactly 78 meters. After laying line again, I took the line of the reel, fixed it to a stone, while Hervé took his data. On the way out we were able to enjoy the cave, which frequently changes its shape and size from landscape to portrait and back.
Getting closer to the shaft we found Micha and Reinhard's scooters, which had been placed there by some deep support divers. We checked all the stages and scooters before proceeding.
Closer to the shaft we also took out some old line, as there was a completely unnecessary T without line arrow.
What followed was the usual decompression procedure after 120 minutes of bottom time, interrupted by drinking and eating plus some bullshitting in the wetnotes.
As Reinhard and Micha would conduct their push dive on the next day, we cleaned up the cave behind us, meaning we took all our equipment out. 4 stages, 2 scooters and a heating tube on each person besides a rebreather between two 20 liter steel tanks may seem a bit of task loaded: however, we did not even notice this amount of equipment.
So this time we scootered towards the entrance, finishing a perfect and successful dive after 5 hours and 37 minutes in water time.