15 September 2005

Weekend at Dersios

In the framework of the ongoing exploration project which began in 2003 a small team of four found ourselves on the Palaiochora plateau at the weekend; there were three cavers and one caver-quartermaster in charge of the food.

We went up on Friday and slept in Tasos' cheesevault about 250m from the cave entrance.

Internal view of the east side of the cheesevault

The purpose of the expedition was to dive the second sump and see what the potential for continuation of the cave through there would be. Our cave diver Nikos Mitsakis had dived both the second sump and the sump in the third sidebranch in 2003. Both come out in a dry section. The section beyond the second sump reaches a third sump a few meters further on, and the section beyond the sump in the third sidebranch ended at the bottom of a pit after quite a distance on foot.

We had begun to empty the sump in the first sidebranch at the end of last week. Nikos had dived here last year to a distance of about 70m without finding a way out, and again last week where he discovered a dry dome with a fissure leading off it too difficult to attempt with the bottles on. The idea was to empty the sump and have a look at this fissure for ourselves.

Nikos and Komninos had put on their neoprene suits ready for the dive. I don't have a neoprene suit, so I didn't wear one. On getting to the entrance to the second sidebranch, I saw both the boys waiting for me there with huge smiles on their faces. Yeah, I was taking my time and they were criticising - or so I thought... they asked me to listen to the hosepipe, again with the huge smiles - I listened... water! Running water! The hose which had been set to empty the sump was still emptying after six whole days!

Almost running, we made our way to the chamber at the end of the sidebranch and feasted our eyes on a most beautiful and satisfying spectacle: passage! Where one week earlier there had been only rock and water, we now saw the water level had dropped by about a meter and new passage opened up and beckoned us into the unknown.

The other two strode off chest deep in water into the unknown and I stayed behind waiting for them I don't recall how much time passed - but at some point they returned, dressed me as fast as possible in Komninos' neoprene jacket, put rope into the sack, left unnecessary weight behind and we all three of us now leapt into the waters. The water was cold enough, but the neoprene is rather good in these conditions, no doubt about that.

This new passage that used to be a sump had a meandering route through chest-high and neck-high water interspersed with completely dry parts. We walked through sections reminiscent of canyons, totally sculpted out of the rock by the waters' passage. We finally reached a large break-down chamber where the sump would empty out as a waterfall in the winter. From there, a few meters further on we got to the first descent. The boys had got this far without me when they had turned back for rope - now I would be taking part in real exploration into the unknown for the first time!

After the first descent, the cave takes a small turn to the right, turning from a course of almost directly south back to the usual sort-of westwardly course we were used to in Dersios.

We went through some meters jammed in between two different rock types - one was stratified horizontally, the other had stratification at an angle of about 55-60 degrees. In between the two, in a gap of about 50cm to 1m the water would flow in the winter. In between the two, either walking or climbing, we continued to push into the unknown.

After a little while we reached another descent which needed to be rigged. This one needed an anchor to be placed also. It was about here that we bgan to run out of rope… we had not in any way foreseen such a long and deep continuation to come out of the sump and all the rope we had with us was of short length and needed to be knotted together. After the second descent, the going was similar to how it was before - a little walking, a little climbing and on to the third descent...

Here, we turned back for the rope we had used to rig the first descent, which had a positive incline and could be easily climbed without rope. I stayed back and the boys carried on as far as the rope would take them. According to their Suunto watches, we were about 120m below the entrance at the point where we turned back.

We turned back to the entrance, full of enthusiasm and totally ready to devour any food placed in front of us!

The well-stocked cheesevault's stores

Waiting for us outside was Niki, probably overjoyed at the news that we were out while the sun was still shining. She prepared the evening meal with the help of Komninos. Theodossis came up from Tyros with walnut cakes and wine. There was no disappointment that the cave dive did not happen: our efforts of the past month had bourne their fruits in the form of new passages. We figured we had discovered about 300m of new passage but the length was less important to us than the fact that the route was beautiful.

Still, we had a lot of unanswered questions. Where does this new passage go? How much further would it go? Would we end up at the top of the pit Nikos had seen in 2003 or somewhere else? Which way does the water go in winter: this way or down the known route?

We all slept soundly with the smile of success on our faces in the company of the little mouse we had found in the cheesevault's cupboard. This was no doubt a cousin of the guys we had seen a few weeks before in the cave - their colouration was identical.

We woke late the second day and did some household chores in the cheesevault. Niki left for the beach with Theodossis and left us to busy ourselves with the survey of the explored section and the completion of the exploration. We commenced our descent de-rigging the unnecessary ropes from the initial descents at the entrance hoping in this way to end up with enough rope to complete the exploration.

In the chamber before the sump we discussed the survey strategy and set off. The first 120m or so were tough, with about 6m between each station and every other station requiring someone to be motionless in the water. The long time in the water was a little tough. After the waterfall Dersios opened up and we were out of the water again.

We reached the spot where I had turned back the day before and the guys rigged the third descent again replacing the completely exploratory rigging with something more sturdy. After this we got to the fourth and last descent where the boys had tried to go down without rope the day before, through the narrow gap between the rocks, but this gap opened out making it impossible to continue. So here it was that the last rope was rigged and the last descent was made in this new section. After the descent, to the right, the cave continues, walking, at a depth of about -140.

Nikos went off down the walking section and Komninos and I took the last measurements on the survey. The walking section ends up at a sump and in the sump we could see the diver's guideline. We had closed a circular route of over one kilometer (it is about 500m to the beginning of the sump from the beginning of the second sidebranch, whichever route you take - new or old.

We came out satisfied and began to prepare to go down to the beach and meet Niki.

Some words about the new sections:

Newly explored / newly surveyed sections (in July 2005): 477m
Newly explored sections beyond the surveyed section: ~100m
Overall length of surveyed section (31 July 2005): 1.381m
Estimated length of explored section (31 July 2005): ~1.700m

Tasks still needing to be done:

Survey of the final section from the last pitch to the sump in the new section.
Drafting of the survey.
Re-survey of the old cave

There are no photos of the new sections, cameras were part of the unnecessary weight left behind. Clicking on the surveys will open up bigger images.

25 July 2005

31 July 2005 plan

31 July 2005 projected section from 285 degrees

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