Log na Sionna / Shannon Pot
Shannon Pot (H0533 3175)
Description and history of diving
This is the rising of the River Shannon, taking water from Shannon Cave and other sinks on Cuilcagh Mountain. It was first dived in April 1971 by J. V. Elliot and Roger Solari, who reached a depth of -6 m at an overhang with a black hole below. Returning in September 1971 they reached -8.4 m to find the water emerging from a long slit 150-300 mm high. Martyn Farr dived in April 1972 and confirmed the previous findings but got no further. In 2009 Artur Kozlowski broke through into a large submerged chamber, the floor of which is at -14 m. This is quite unstable.
Cave Diving Group Newsletter, 22; 24
Irish Speleology, 3.2, 1985
Irish Sump Index, 1988
The caves of Fermanagh and Cavan, 1997
Irish Speleology, 18
20-12-2008 - divers Al Kennedy and Paul Doig
First dive together ended in confusion and entanglement with trees at -2 m. Second dive made solo by AK also ended in entanglement with a large tree at -3.7 m. Leaking regulators curtailed any further exploration. Visibility was extremely poor, about 0.5 m, the water is heavily stained. Progress was mostly by feel. Upwelling current was noted on the surface of the pot.
17-01-2009 - divers Artur Kozlowski, Al Kennedy and Paul Doig
Navigating among submerged trees and belaying unorthodoxly to tree branches Artur reached gravel bottom of the pot at -7 m sloping eastward. After two meters or so an overhanging section of rock appeared and the way on seemed to be situated underneath through a tight slot partially blocked by large cobbles and a few small boulders. They were all very rounded and situated on an unstable slope of 30 degree. This section looked very washed and clean with good visibility of 1 m. After 10 minutes of work the slit was enlarged enough to be entered. After one meter another low section was enlarged /negotiated after which passage opened up comfortably to at least 2x1 m. Moving very slowly down the steep slope no obvious belay points could be found - some smaller boulders were sitting out of the gravel bottom but the diver didn't dare pull out any of them fearing that would destabilize the whole slope. The right hand wall was irregular and few projections that looked like solid hard limestone simply broke off when he tried to belay to them - they turned out to be very soft and brittle. It was the same about some smaller boulders - they just fell apart when he tried to wrap snoopy loop around them. Line was tied off to the first encountered loose cobble 10 m into the cave at -13 m. Total dive time 25 minutes.
On his second dive Artur reached EOL in matter of minutes and continued for another couple of meters to the bottom of the slope at -14.7 m of depth. A strong current was emerging from a shaft in the floor. It was tight and looked extremely unstable - walls consisted of small, loose boulders. The diver continued over the shaft and a 2 m long linear depression in mixed gravel/cobble bottom. When one of cobbles was lifted large quantities of sand started sinking rapidly into the bottom. Unsure what was going to happen next diver plugged the hole in the floor again! After a total of 20 m from cave entrance the wall seemed to close down. Al and Paul dived next and surveyed the cave along the line confirming existence of substantial chamber at the bottom of the slope and around the shaft.
24/01/2009 - divers Paul Doig and Al Kennedy
A few days of high rain fall has made a considerable change inside the chamber. Obviously a high water flow creates a very violent environment inside the chamber with rocks and gravel being tumbled like a washing machine. The gravel coverage was changed and larger rocks had been moved including changing the entrance, which was now harder to negotiate.
The bottom of the shaft was now visible on this dive and seen turning to the north 1.5 m down.