Polltoophill, Castletown River Sink
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Final sink of Castletown river, 1.2km in straight line from Polldeelin. In early 90's Garda diver who went down there on base fed line in search of weapon of murder but after reaching -20m he signaled to pull him out. His colleagues managed to do it with great difficulty against the current. Among the locals Polltoophill is known as the place where river sinks clockwise - in most water conditions you can see water in a sink pool circulating anticlockwise.
17.05.2008
Divers: Artur Kozlowski, Brendan O'Brien
It was obvious that anyone who had in mind Polldeelin - Polltoophill traverse will have to face that challenge one day.I was monitoring flow in the sink for last 2 months and on Saturday I decided to give a try with 8mm line and Brendan's support. At the foot of the cliff there seems to be big collapse starting just under the water level with sheer wall on the south side. I dived first along that wall but after dropping to -16m among submerged mature trees I found only short blind pot. So I came back to the surface , attached my line/rope 1m below water level to substantial boulder underneath the cliff and started my way down from there along steeply descending slope. On about -19m when I was already in overhead for a good while my 8mm line run out. During the next dive I reached -39.4 of depth laying 80m of line in total. At the end of the line cave leveled out:there's vast plateau, smooth floor with only thin layer of silt. Brendan dived next, explored passage for further 20m and confirmed extension of that strange plateau for that distance both ahead and to the left! ( there should be wall in short distance to the right, I moved away from it to avoid to run into deep undercut). Apparently we are in a big chamber or some enormous passage ( of which this river in known by the way).
24.05.2008
Divers:Artur Kozlowski, Brendan O'Brien
We were both better equipped and prepared for the job than previous weekend however passage conditions seemed to deteriorated since then. Once on -40m I was trying to avoid undercut on the right hand side but the floor is completely devoid of belay points. I tried to use anything including some substantial tree branch... After adding 50m of new line or so I dropped my negatively buoyant reel on the floor and we decided to return. At this point visibility was quite bad and we both had impression that we passed some low sections without proper belaying. I did some quick compass survey on the way out and the outcome was quite surprising: initially passage descends in SE/S direction just to turn toward West after 50m... Polldeelin Main Rising where this water is believed to resurge is situated NW. Weird, it seems like the passage is going to smaller Castletown River sink - Castle sink, which is situated 300m upstream.
7.06.2008
Divers: Artur Kozlowski, Brendan O'Brien
We dived together. 40m of line added. I tied off the line on -45.5m. To our surprise ( again...) passage is heading W and SW... On a deco stop, between 3 and 5m I came across some very interesting features looking like a fossils of some moluscus. After consultation with Matthew Parkes from Natural History Museum they turned out to be fossilised corals within the Carboniferous Limestone from which the cave passages are dissolved. They were once like thick cabbage plant stalks on the sea floor with the soft animal living in the uppermost section. They are are often preserved silicified, so do do not dissolve like the limestone around them.
Fossilissed corals in Castletown River Sink 1
Fossilissed corals in Castletown River Sink 2
08/06/08
Divers: Jim Warny, Jonathan White and Brendan O'Brien
Divers added 80m of line. They reached 47.5m of depth.
20.07.2008
Diver: Artur Kozlowski
My fifth dive in Polltoophill. Flow at the surface strong but it's not an issue once underwater. I had a plan for 40min on 48m but it turned out that 47.5 reached by lads at the beginning of June was the deepest spot so far - after that way on started going up to finally level out on ~40m. It also changed direction from W to NW which is exactly what I wanted - straight to Polldeelin ( Polldeelin passage turned SE). I added around 80m of line from 150m reel which has been left at the EOL ~320m from the surface. I reckon there's ~500m left to join the lines.
28.07.2008
Diver: Artur Kozlowski
First 250m vis was quite clear, with good 2m of visibility but after that it reduced to 1m - more particles and I have even thought that maybe I have already swam over that place...Smiley After adding 50m of line on 43m I came across PP line, definitely mine...I knew it could't be Polldeelin line, that was too far but I marked it with double snoopy loop, tied off EOL and started my return... Of course, after 120m I arrived to double snoopy loop...
21.02.2009
Divers: Jim Warny, Artur Kozlowski
On the surface the sink was full of floating rubbish - bottles, shoes, tyres, wheels, gas tanks, logs to name only few. Jim located my 9mm main line at -1m and off we went. On -14.5 we found the line cut and torn into pieces. Without wasting the time Jim attached his 120m reel.We navigated our way among tree branches, substantial wooden logs and other flood debris - all that came last winter. Two people on steep downstream slope plus belaying process resulted in very low visibility, in the range of 0.5 m. Once we reached familiar plain on -40m vis improved to 1m. We cut that vast plateau across and continued along left hand side wall at -45m heading South but still downstream as the flow indicated. Water was 6.3 degree and after 45 minutes we both started feeling our fingers going numb. When Jim finished his 120m reel we started return. We finished the dive uneventfully after 96min. New EOL 140m in.
22.02.2009
Divers: Jim Warny, Artur Kozlowski
We returned next day reaching EOL in 10 minutes. Finding the way was even more awkward, I followed Jim closely checking compass directions and trying to make sure the line wasn't caught anywhere. After adding 60m of new line (strong, indicative current at the end, passage turning West) we turned back enjoying good, 1m+ visibility. Back to the surface after 72min. EOL 200m
07.03.2009
Diver:Artur Kozlowski
CCR Megalodon. I went off with 100m reel. At 230m I came across my old 4mm line but I kept on putting new 6mm line - this year I decided to follow only flow indication as the last year too much compass reliance resulted in making a loop to my own line. 40m from old EOL I stuck in some some nasty section of deep and soft flood debris. I tried to fly over it quickly but I felt a need for belay point and had to land pretty much in the middle of that. No way to read handsets but HUD worked fine and finally a belay was made. Nevertheless I did not want to push it and made my way out surfacing after 99min. Water somehow warmer, around 10 deg.
22.03.2009
Divers: Artur Kozlowski
CCR Megalodon. I quickly regained EOL 250m in. I continued over mud banks which luckily disappeared after few metres. Soon I arrived to the edge of some deep rift running perpendicular to the way I was heading (NW). Again I decided to trust the flow and I crossed over the rift swimming for good 7-8m in mid water with no point of reference until I landed on some relatively clean bottom with well defined NW flow. I continued until I run out of line 300m in. Good dive, 111m runtime, water still 10 deg. Quite a flow on -14m on the way out.
11.04.2009
Diver:Artur Kozlowski
I arrived to Castletown on Saturday morning and set up my camp on the hill overlooking Polltoophill sink. I brought 320m of line on three reels and the plan was to take advantage of wet weather and strong flow to establish the connection with Polldeelin rising in Kiltartan (EOL in Polldeelin, according to my estimation, shouldn't have been more than 400m away from EOL in Polltoophill). Dive on Saturday proved to be excellent with extra 170m of line laid on one go. Depth was constant -40m, flow strong and indicative, very little trouble to find the way on. Water was very warm, 12deg and 140min runtime was not a problem. EOL 470m in.
12.04.2009
Diver:Artur Kozlowski
Due to various equipment problems I reached my yesterday's EOL at 470m in 30min ( instead of planned 20min).From there on everything was going smooth, I attached new 100m reel and I was moving on in well defined passage heading NW (good, towards Polldeelin Rising) on constant -40m with substantial flow confirming the way on. And then the passage started dropping down although very gradually. When I reached -46m I started wondering if I wasn't back to 150m from the entrance where the cave had it's deepest point, -47m. On reaching -50m relief was mixed with surprise. I certainly wasn't back to beginning, the passage was firmly heading NW and dropping steadily. On -51 or -52m line on 100m reel finished but I felt comfortable enough and attached another 50m reel double checking on the same occasion my narcosis level which turned out to be surprisingly satisfying. After having laid 10m or so of line on continuing gentle slope and reaching -55.3m (which is now second greatest depth in Irish sump) I decided it was enough. It became obvious there would be no immediate connection with Polldeelin. Not for a while at least( EOL in Polldeelin is at -36m, 830m in). Turning back was actually quite a good idea as the flow I had to fight against on my way out was very strong. Couple of times I had to stop to take a rest and to calm down my breathing - I wasn't on OC anymore and CO2 buildup was a real threat. Run time 155 min. All 6m deco on OC. EOL 580m
12.05.2009
Diver:Artur Kozlowski
Flow in the sink was strong but not prohibitive. Last month brought lot of silt and flood debris and on the top of that visibility was barely 0.5m. I reached end of my line in 35 minutes and continued for another 40m at constant depth of -55m. I attached another reel and continued with current reaching -62.5m somewhere 680m in the cave. From there passage started ascending to level out on -58m. 1h into the dive I dropped my reel and started return. It took me 40 min to reach my first stop at -27m. I did all intermediate stops flying the unit manually between 1.5 and 1.6. On -6m I switched to open circuit oxygen staying there for 1h15min including "air" break. Final ascent was 1m per minute and surface was reached uneventfully after 3h45min. Water temperature 14 deg. Diluent used Tx 20/42. EOL 720m.
31.05.2009
Diver:Artur Kozlowski
Despite good couple of days of a dry weather water levels were still quite high, as was the current. EOL, 720m in, has been reached in 45minutes. From there progress was as usualpainstakingly slow and in nil visibility. The cave continued on -60m. 800m into the cave floor started rising gradually, first into fifties , to finally leave me with empty reel at -48m. Ascending passage was reasonably clean with light grey wall on left hand side. Very similar to the passage at the EOL in Polldeelin which was at -38m. The water temperature, even at the bottom was 19 degrees. Runtime 4.5h EOL 850m.
13.06.2009
Divers:Artur Kozlowski, Brendan O'Brian, Frank Griga
I have laid 220m of new line extending EOL to 1070m. From -62m 720m in the cave started ascending gradually in 4m wide uniform passage. I reached my previous EOL in 50min and continued in that ascending passage for another 220m to a surprising depth of -23m. I was thankful that finally I was run out of line as i wasn't really sure that I could go that shallow without stops. Beside of that my bottom time was already 1h 25min so it was high time to go home. I left empty reel as a belay point ( I was run out of snoopy loops by then) and started moving fast towards exit. I arrived to my first deco stop at 30m in 2h 20min where I find vis to be very bad. I had some worrying thoughts about what might possibly had happened on the surface ( normally you don't expect bad vis swimming upstream) but I continued my deco, on Meg, flying manually on 1.5, then finish half of my 6m/O2 stop on open circuit. Plus 10min ascend to the surface from there. Once on the surface I was told about mad thunderstorm that rolled over Gort - streets were flooded with water getting into some shops... and that's the cause of that bad visibility at the end. Total dive time 5h15min.
