Exploration of Sintzi Spring, the deepest cave of Greece
Sintzi spring (gr. Πηγη Σιντζι) is the deepest underwater cave of Greece, located in the middle of picturesque heights of Peloponnese Peninsula. Our first contact with this cave took place in May 2023. We spent a week diving in the corridors of Sintzi, getting to know the cave, and checking the potential leads. The cave morphology is very interesting, with many crossings, side branches, twisted corridors, and two deep shafts. From the information we had, the first, tight shaft, was explored in the past to a depth of -94 meters, and the other, vast one, to a depth of -186 meters in 2015.
During our dives in Sintzi, supported by Mariusz Banaszak I managed to reach the EOL in the shaft at -94 meters. It turned out that there is a continuation, but there is an obstacle - a tight restriction. I managed to squeeze through in my backmount Liberty CCR, but the process was not comfortable, and I didn't want to push further. Now we had a confirmation that there is at least one lead that can be explored in the future - an inviting corridor with no guideline.
Last few days of our expedition were focused on the other, deepest shaft. Over a few days' diving we've managed to fix broken guidelines, lay down safety tanks, and on the final dive I descended down to -170 meters depth. The shaft still went straight down, and there was no bottom to be seen. That was the end of 2023 expedition.
We almost immediately decided, that we have to return to Sintzi the following year. So in May 2024, though with a different team (Mariusz couldn't come due to work-related reasons), I was back in Arkadia. This time my plans were more bold:
1) passing the restricition at -94 meters in a sidemount Liberty CCR and laying new guideline
2) reaching the current end-of-line in the deepest shaft at -186 meters and probably adding some new line if there will be a continuation.
During over a week of diving focused solely on Sintzi, I've made a few preparatory/conditioning dives, set up open circuit bailout tanks and fixed broken guidelines in the deeper sections of the cave. Then it was finally time to start exploring!
My first shot was the corridor behind the restriction. Passing the tight section (photo in the gallery below) in a sidemount rebreather was much, much simpler than in a backmount CCR. After 20 seconds, I was on the other side and ready to start exploring. With a reel inone of my hands, and a Seacraft DPV in the other - I set off into the unknown parts of the cave. The corridor was still going deeper with a wide cross section. On the second day of exploration, upon reaching a depth of -160 meters, I spotted a guideline in front of my eyes - it took me a few seconds to realize that the corridor I explored has connected with the shaft leading into the deepest parts of the cave! I added over 100 meters of line before reaching that connection.
When exploration of the shallower shaft was over, I still had a few days I could spend on reaching the deepest explored sections of Sintzi. After a day's break, I returned to the cave, focused on descending down the main, deepest shaft. One dive was not enough to reach the bottom, but it was enough to make me want to go back again the next day: at -180 meters depth, the bottom of the shaft started to be seen. There was a small, black item to which the guideline was going - a reel of the previous explorer! But an even more interesting thing was a few meters to the left - a big, dark shadow, that could only mean that there is some kind of cavity - or corridor - in there!
The next dive's objective was to reach the reel on the bottom, around -190 meters depth, look into the "shadow" in the wall for a potential lead, and in case it will be there - secure the existing line to a rock, attach my own reel full of new guideline, and take the old reel up to the surface after nine years on the bottom. When I reached -190 meters and pointed my light on the wall, it became clear - there is a wide corridor in there! Excited, I proceeded with the plan, and after a 5-hour-long dive I was back on the surface, planning the last, final push dive.
My assumptions for the final dive were to spend maximum of 7 minutes on the bottom and in the new corridor (6 hours total dive time), and in case the corridor will continue going down, the maximum depth I allowed myself to reach was 240 meters. After reaching my reel I checked the bailout Liberty Sidemount CCR I had with me, and immediately put my DPV on "9th" (highest) gear, which allowed me to move with a speed of around 60 meters per minute. That's fast. The visibility was perfect, and the corridor kept continuing. After three minutes of exploration, the depth went beyond 230 meters, but there was still continuation. I felt good, with clear mind, no signs of HPNS, so I decided that I'll continue for another half a minute, and then turn back. After 10 or 15 seconds, the corridor started going down again, and my dive computers showed -240.0 meters. At this very moment, I turned around, cut the guideline, and started a full-throttle way back.
During the ascent I collected all the safety bailout tanks, and met with Jacek & Agnieszka Strejczyk on one of the decompression stops. I signalled "all okay" and showed them the computers with maximum depth recorded. Aga took an amazing picture of me. After another few hours (6.5h total dive time) I resurfaced. There was Michał and Beata waiting on the shore in case any support would be needed.
On this dive I explored over 150 meters of new cave, deepening it to -240 meters, and there's still more to go. Overall during this expedition, supported by the team I've managed to add more than 250 meters of guideline, find a connection between the two deep shafts, and deepen the cave by more almost 60 meters (-186 -> -240). That was a very, very fruitful and interesting time. All of my dives were recorded, and the the resulting movie can be seen below - make sure to check it out!
Sintzi Spring 2024 expedition team:
Bartłomiej Pitala
Beata Ziemann
Agnieszka Strejczyk
Michał Rachwalski
Jacek Strejczyk
Erikos Kranidiotis
Stelios Stamatakis
