Projects > Doux de Coly 03
The Winch Team
Latest update: March 18, 2004
The final check of the two person habitat in front of the chalets in "La Grande Prade ". For transport under water, the habitat is disassembled.
To get the maximum benefit of the new two person habitat,
it is necessary to lift it up from 27 m to the last stop at 9 m
in the deco phase. A 18 m distance
for 1,5 tonnes of positive buoyancy is too much
for a conservative tackle with ropes. The solution
was a wire rope lifting unit, also known under the brand name "Greifzug" or "Trifor".
It is a huge winch.
A pure mechanic tool, working with a special steel cable which allows a free pulling and lowering under load by hand. Basically it is not created for underwater use but it can still work under extreme conditions, like in a sandy or muddy environment.
During the tests earlier, the "Greifzug" worked perfect with the habitat even under water.
The tests were done in a big quarry near the city of Hemmoor in the north of Germany, where the habitat and "Greifzug" could attached to a big building under water.
Each movement of the big handle pulls the cable no more than one cm under load. This means it takes several minutes to lift up the habitat to next stop. 500 kg of steel-weights were fastened to the inflated habitat for reducing the positive buoyancy. Each steel-weight had around 20kg and it was a pretty cool experience for the divers who had to transport these to the shaft.
Götz and Andy with the blue inflatable transport drum.
Saturday
Andi and Götz had worked with the "Greifzug" during the test phase in the German quarry. Directly on our arrival day in the evening Andy and Götz started to bring in the complete unit with the help of an inflatable transport drum. Sounds easy but with a big negative drum in the muddy sump pool we "crawled" into the cavern zone and better visibility.
During our "lake" tests, there was no ceiling, but this time Andi couldn't move free with the negative drum clipped on his harness. An additional 25 kg lift bag brought back the neutral buoyancy and the trip to the shaft went on. Arriving at the working area we separated all parts and unrolled the steel cable. The vis was getting worse and we tried a few times to set the cable in the pulling unit but it didn't work. The pressure gauge showed it was time to call the dive for today.
The habitat in the shaft. In the middle of the picture, you can see the "Greifzug" with the long handle and some of the "nice" 20 kg weights.
Sunday
Andy and Götz made a second try to fix the "Greifzug". Parallel with us a second team, Viktor and Gertjan, prepared the fix point for the habitat at the bottom of the shaft.
After taking some time at hammering the cable and cleaning the mechanics, we were able to assemble the unit in the end. We attached the pulling unit on the habitat and went down to the shaft and secured the big carabiner. At the end of this dive the habitat was secured on the bottom with the "Greifzug" unit. A rope at the top of the shaft together with a mountaineering clamp should prevent any uncontrolled descent. That was the plan and all looked fine when we left the scene. That was the plan and all looked fine when we leave the scene.
Monday
During the night the habitat lost air which is normal. The bad thing was that the rope securing it did not stop the descent due to the fact that a diver had displaced the rope inside the moutaineering clamp and so in the end the habitat ended up down the shaft.
Götz and Andy did a perfect job.
Some more work needed to be done at different places. We begun with a double team of Andi and Götz, Thomas and Alex. First Alex and Thomas re-arranged the rope and checked the mountaineering clamp.
After we deflated the habitat and hung it on the rope so the steel rope from the bottom was loosened.
Hence, Andi and Götz could sort out the entangled steel rope on the bottom of the shaft. Because they worked directly under the habitat, Alex and Thomas continued to deflate it and took care that the habitat stayed in place. Due to exhaust bubbles, it might have floated up which could have got us stuck between the steel cable and the rocks.
After everything was in place again, we lifted the habitat up with the help of the "Greifzug" unit: This was also the function check for the system.
That day we made two dives.
Tuesday
Andi and Götz did a final test dive. The habitat was fully inflated the day before and so they checked for any sign of cracks or deformed parts. Everything looked fine, ready for the push dive!
Wednesday
During the deco phase of Reinhard and Micha's dive, nearly all support diver had to move the habitat by pumping with the "Greifzug". We were glad to see that everything worked fine.
Great teamwork from everyone at the Doux de Coly 2003.
Safe dives, Andi, Götz and Thomas