John Thomas' Hole
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Location
John Thomas' Hole (H1186 3411)
Description and history of diving
Reputedly the muddiest cave in County Fermanagh! Lake Chamber is a submerged pot that connects with the Sruh Croppa River at a depth of -12 m. Diving appears to have revealed the junction of the Sruh Croppa and the Aghinrawn rivers some 20 m downstream of the pot. The combined waters resurge in Lower Cradle Hole.
The pot was first dived in 1978 by Martyn Farr, who laid 45 m of line to a maximum depth of 16 m and stopped at the low section. The next dives were in 2009 by Al Kennedy and Artur Kozlowski. Kozlowski has extended the line to 60 m and a depth of -18 m, but all ways on seem to close down in boulders.
References
Irish Sump Index, 1988
The Caves of Fermanagh and Cavan, 1997
Surveys
None entered.
Recent dives
15-03-2009 - divers Al Kennedy and Artur Kozlowski; support Niall Tobin and Ciara O'Hagan
Carrying two 7L cylinders and harnesses through the complex of crawls, climbs and traverses to Lake Chamber the support of Niall and Ciara was much appreciated!
Al dived first. In trying to climb high enough out of the water in Pool Chamber to check the condition of MF's primary belay the silt was disturbed. Tugging suggested that it was still secured to something in the boulder slope, and descent was commenced in visibility of 15 cm or less. Going slowly and checking the condition of the line, at -2.5 m the diver was startled by a fall of boulders and rapidly ascended in case the primary belay was going to follow. With the line seemingly still secure the descent was commenced again. The top section of the pot was loose boulders and silt, but this gave way to bare rock. The line dropped almost vertically to -12.8 m, trending south-east, and here the diver felt the line going into a constriction. The visibility varied from 15 to 30 cm, as slight current of Sruh Croppa here cleared disturbances. Unhappy with where the line was going, the diver sought for a belay to hold it out of the bedding plane, but after feeling around for a minute or so could find nothing for snoopy loops or silt screws and decided the best option was to ascend.
Artur then dived, in a semi-dry, dropping rapidly to the junction with the Sruh Croppa. Leading the line to hold it out of the constriction the diver crawled downstream in very poor visibility, the silt disturbed travelling along in the current. No belays were encountered on the way to MF's EOL, so several were added for peace of mind. At MF's EOL, where the line disappeared into the sand, a new line was added and the constriction, about 0.5 m high, was passed, the passage becoming higher again after several metres. 8 m of additional line were laid (total now 53 m), the way on being open. The passage deepened slightly to -18.1 m - the EOL diving upstream from Lower Cradle Hole is -17 m, and the connection must be very close. 'Madly cold', the diver returned to base, making his report through chattering teeth.
The water temperature recorded was 6 degrees C.
04-04-09 & 06-04-09 - diver Artur Kozlowski; support Niall Tobin
On 04-04-09 with the help of Niall Tobin a pair of 12 L cylinders were carried to the Lake Chamber.
On a solo trip on 06-04-09 a 5.5 L bottle and the rest of the diving kit was carried in and the sump was dived in a three tank configuration (2x 12 L and 5.5 L). This time in drysuit, buoyancy control was better and reasonable 1 m visibility was retained for the first 50 m. After 20 m the diver have noticed the beam of his light dimming gradually, believed to be due to darker water entering on the right - most probably the Aghinrawn River. Reaching the previous limit at -18 m and 53 m into the sump the left wall started turning to the right and soon reached a boulder choke with some flow visibly flowing in and up. Ascending to the roof, which was quite high again after the low section, but there were boulders there too. After a dive of 1 hour no way on was found. Line cut off 60 m from base.
