92-514: Shannon Cave is an active stream passage cave which straddles the border of County Fermanagh , Northern Ireland and County Cavan in the Republic of Ireland . At 130 metres (430 ft) vertical depth, it stands joint sixth with Poulnagree in County Clare in the deepest caves on the island of Ireland . The cave is recorded at 5.4 kilometres (3.4 mi) in length (making it the sixth-longest on
184-633: A Catholic background, according to the 2011 census . Fermanagh spans an area of 1,851 km (715 sq; mi), accounting for 13.2% of the landmass of Northern Ireland. Nearly a third of the county is covered by lakes and waterways, including Upper and Lower Lough Erne and the River Erne . Forests cover 14% of the landmass (42,000 hectares). It is the only county in Northern Ireland that does not border Lough Neagh . The county has three prominent upland areas: The county borders: Fermanagh
276-447: A LiDAR point scan of the descent into Poltullyard was premiered at IDFA 2023 The experience is based on a series of still scenes rendered using proprietary point cloud technology on Unity and runs on the Quest 2 . County Fermanagh County Fermanagh ( / f ər ˈ m æ n ə / fər- MAN -ə ; from Irish Fir Manach / Fear Manach , meaning 'men of Manach') is one of
368-572: A Senior Provincial or an All-Ireland title in any Gaelic games, it is only one of two counties to win neither title. There are 22 GAA clubs in the county, this is the second least of all 32 counties (Longford now has the least, with 21 GAA clubs). Only Ballinamallard United F.C. take part in the Northern Ireland football league system . All other Fermanagh clubs play in the Fermanagh & Western FA league systems. Fermanagh Mallards F.C. played in
460-470: A breakdown of what factors contributed to the accident. Despite the unique circumstances of each individual accident, Exley found that at least one of a small number of major factors contributed to each one. This technique for breaking down accident reports and finding common causes among them is now called accident analysis , and is taught in introductory cave-diving courses. Exley outlined a number of these resulting cave-diving rules, but today these five are
552-403: A combination of these conditions. Losing the guide line in a cave is a potentially life-threatening emergency. While following recommended best practice makes it highly unlikely that a diver will lose the line, it can and does happen, and there are procedures which will usually work to find it again. Any reliable information on where the diver is likely to be relative to the last known position of
644-810: A community discussion and analysis of accidents through a "Cave Diver Safety Meeting" held annually. Equipment used by cave divers ranges from fairly standard recreational scuba configurations, to more complex arrangements which allow more freedom of movement in confined spaces, extended range in terms of depth and time, allowing greater distances to be covered in acceptable safety, and equipment which helps with navigation, in what are usually dark, and often silty and convoluted spaces. Scuba configurations which are more often found in cave-diving than in open water diving include independent or manifolded twin cylinder rigs, side-mount harnesses, sling cylinders , rebreathers and backplate and wing harnesses. Bill Stone designed and used epoxy composite tanks for exploration of
736-415: A dive, and the monitoring and switching of breathing gases during a dive, and the provision of emergency gas to another member of the dive team. The primary aim is to ensure that everyone has enough to breathe of a gas suitable for the current depth at all times, and is aware of the gas mixture in use and its effect on decompression obligations and oxygen toxicity risk. The rule of thirds for gas management
828-503: A lack of temperature extremes, according to the Köppen climate classification . The National Trust for Places of Historic Interest or Natural Beauty manages three sites of historic and natural beauty in the county: Crom Estate , Florence Court , and Castle Coole . The oldest sediments in the county are found north of Lough Erne. These so-called red beds were formed approximately 550 million years ago. Extensive sandstone can be found in
920-446: A larger volume of gas than he alone requires. A different option for penetration dives is the Half + 15 bar (half + 200 psi) method, in which the contingency gas for the stage is carried in the primary cylinders. Some divers consider this method to be the most conservative when multi-staging. If all goes to plan when using this method, the divers surface with stages nearly empty, but with all
1012-546: A light and not realize how far away from the entrance (and daylight) one has swum; this rule is based on the theory that, without a light, divers will not venture beyond daylight. In the early phases of cave-diving the analysis shows that 90% of accidents were not trained cave divers; from the 2000s on the trend has reversed to 80% of accidents involving trained cave divers. Modern cave divers' capability and available technology allows divers to venture well beyond traditional training limits and into actual exploration. The result
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#17328524184431104-441: A method that would be ideal for one situation might not work at all for another. If the line is found, but not the other divers, the diver can tie off their search reel to the guide line as an indicator to other members of the team that they were lost but have found the guide line, and indicate the direction that they intend to proceed along the guideline with a personal directional marker so that others who see it while searching for
1196-442: A search, which will depend on the stage of the dive when the diver is noticed to be missing. When searching in darkness, the searchers should periodically turn off their lights as this will allow them to see the lost diver's light more easily. Gas planning is the aspect of dive planning which deals with the calculation or estimation of the amounts and mixtures of gases to be used for a planned dive profile . It usually assumes that
1288-417: A section of the choke collapsed on Rev. George Pitt while he attempted to force a passage at river level. He became trapped for 10 hours, but was freed after a major rescue effort. By 1990 the explorers had passed the newly named George's Choke. The end of the cave was reached, 400 metres (1,300 ft) downstream, at the terminal sump (sump 3) beneath another large boulder choke, and the extension to this point
1380-537: A self-taught approach is discouraged. The following training courses are offered by the listed organisations: Diver In France, courses organized by the national cave diving commission of the FFESSM , are offered to holders of level 2 certification or higher. The French Cave Diving School of the FFS also offers courses open to any autonomous diver . A significant aspect of cave diving by competent and enthusiastic cave divers
1472-467: A single dive. While a less-intensive kind of diving called cavern diving does not take divers beyond the reach of natural light (and typically no deeper than 30 metres (100 feet)), and penetration not further than 60 m (200 ft), true cave-diving can involve penetrations of many thousands of feet, well beyond the reach of sunlight. The level of darkness experienced creates an environment impossible to see in without an artificial source of light even if
1564-584: A technical diving challenge. Underwater caves have a wide range of physical features, and can contain fauna not found elsewhere. Several organisations dedicated to cave diving safety and exploration exist, and several agencies provide specialised training in the skills and procedures considered necessary for acceptable safety. Two types of overhead diving environment are defined in recreational cave diving: The underwater cave environment includes those parts of caves which may be explored underwater. Recreational cave diving can be defined as diving underground beyond
1656-548: Is Enniskillen ( Inis Ceithleann , 'Ceithleann's island'). The island town hosts a range of attractions including the Castle Coole Estate and Enniskillen Castle , which is home to the museum of The Royal Inniskilling Fusiliers and the 5th Royal Inniskilling Dragoon Guards . Fermanagh is also home to The Boatyard Distillery, a distillery producing gin . Attractions outside Enniskillen include: The classification of settlements by NISRA defines six categories following
1748-546: Is underwater diving in water-filled caves . It may be done as an extreme sport, a way of exploring flooded caves for scientific investigation, or for the search for and recovery of divers or, as in the 2018 Thai cave rescue , other cave users. The equipment used varies depending on the circumstances, and ranges from breath hold to surface supplied , but almost all cave-diving is done using scuba equipment , often in specialised configurations with redundancies such as sidemount or backmounted twinset. Recreational cave-diving
1840-418: Is a rule of thumb used by divers to plan dives so they have enough breathing gas remaining in their diving cylinder at the end of the dive to be able to complete the dive safely. This rule mostly applies to diving in overhead environments, such as caves and wrecks, where a direct ascent to the surface is impossible and the divers must return the way they came. For divers following the rule, one third of
1932-548: Is an increase of cave-diving accidents, in 2011 the yearly average of 2.5 fatalities a year tripled. In 2012 fatalities reached the highest annual rate to that date at over 20. As response to the increase in fatalities during the years 2010 onwards, the International Diving Research and Exploration Organization (IDREO) was created in order to "bring awareness of the current safety situation of Cave Diving" by listing current worldwide accidents by year and promoting
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#17328524184432024-519: Is by far the least populous of Northern Ireland's six counties, with just over one-third the population of Tyrone , the next least populous county. It is approximately 120 km (75 mi) from Belfast and 160 km (99 mi) from Dublin . The county town, Enniskillen, is the largest settlement in Fermanagh, situated in the middle of the county. The county enjoys a temperate oceanic climate ( Cfb' ) with cool winters, mild humid summers, and
2116-550: Is coming up out of the Earth and flowing out across the land's surface. Siphons have in-flowing currents where, for example, an above-ground river is going underground. Some caves are complex and have some tunnels with out-flowing currents, and other tunnels with in-flowing currents. Inflowing currents can cause serious problems for the diver, as they make the exit more difficult, and the diver is carried to spaces that are unfamiliar and may be dangerous, while outflowing currents generally make
2208-407: Is ensured by the use of a continuous guideline between the dive team and a point outside of the flooded part of the cave, and diligent planning and monitoring of gas supplies. Two basic types of guideline are used: permanent lines, and temporary lines. Permanent lines may include a main line starting near the entrance/exit, and side lines or branch lines, and are marked to indicate the direction along
2300-409: Is exploration, survey and mapping. Data collected is often shared and may be stored on databases to help optimise the effectiveness of such surveys, and make the information generally available. Underwater cave mapping is complicated by both a lack of access to the surface for GPS positions, darkness, with short line-of-sight, and limited visibility, which complicate optical measurement. Altitude/depth
2392-437: Is generally considered to be a type of technical diving due to the lack of a free surface during large parts of the dive, and often involves planned decompression stops. A distinction is made by recreational diver training agencies between cave-diving and cavern-diving, where cavern diving is deemed to be diving in those parts of a cave where the exit to open water can be seen by natural light. An arbitrary distance limit to
2484-496: Is relatively simple as accurate depth measurement is available to divers in the form of decompression computers, which log a depth/time record of reasonable accuracy and are available for instantaneous readout at any point, and depth can be referenced to the altitude at the surface. Vertical dimensions can be directly measured or calculated as differences in depth. Surface coordinates can be collected via GPS and remote sensing, with varying degrees of precision and accuracy depending on
2576-472: Is statistically much safer than recreational diving due to the much larger barriers imposed by experience, training, and equipment cost, but there is no definitive statistical evidence for this claim. There is no reliable worldwide database listing all cave-diving fatalities. Such fractional statistics as are available, however, suggest that few divers have died while following accepted protocols and while using equipment configurations recognized as acceptable by
2668-438: Is to ensure that for all reasonably foreseeable contingencies, the divers of a team have sufficient breathing gas to safely return to a place where more breathing gas is available. In almost all cases this will be the surface. Gas planning includes the following aspects: The primary breathing apparatus may be open circuit scuba or rebreather, and bailout may also be open circuit or rebreather. Emergency gas may be shared among
2760-447: The April 1981 Fermanagh and South Tyrone by-election , shortly before his death. On Census Day 27 March 2011, the usually resident population of Fermanagh Local Government District , the borders of the district were very similar to those of the traditional County Fermanagh, was 61,805. Of these: On Census Day (2021), the usually resident population of Fermanagh Local Government District ,
2852-640: The Leinster coast c. 216 BC . They later settled around Lough Erne , becoming known as the Fir Manach, and giving their name to Fermanagh and Monaghan . Mongán mac Fiachnai , a 7th-century King of Ulster , is the protagonist of several legends linking him with Manannán mac Lir . They spread across Ireland , evolving into historic Irish (also Scottish and Manx) clans. The Annals of Ulster which cover medieval Ireland between AD 431 to AD 1540 were written at Belle Isle on Lough Erne near Lisbellaw . In
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2944-788: The Lough Allen basin. The basin is estimated to contain 9.4 trillion cubic metres of natural gas , equivalent to 1.5 billion barrels of oil . The county is situated over a sequence of prominent faults, primarily the Killadeas – Seskinore Fault , the Tempo – Sixmilecross Fault , the Belcoo Fault and the Clogher Valley Fault which cross-cuts Lough Erne. The Menapii are the only known Celtic tribe specifically named on Ptolemy 's 150 AD map of Ireland , where they located their first colony—Menapia—on
3036-651: The Women's Premier League until 2013. Enniskillen RFC was founded in 1925 and is still going. There is also a rugby league team, the Fermanagh Redskins Famous football players from Fermanagh include – Famous people born, raised in or living in Fermanagh include: The most common surnames in County Fermanagh at the time of the United Kingdom Census of 1901 were: Cave diver Cave-diving
3128-412: The thirty-two counties of Ireland , one of the nine counties of Ulster and one of six counties of Northern Ireland . The county covers an area of 1,691 km (653 sq mi) and had a population of 63,585 as of 2021. Enniskillen is the county town and largest in both size and population. Fermanagh is one of four counties of Northern Ireland to have a majority of its population from
3220-408: The 2001, 2011 and 2021 censuses, where noted with an "N/A". Baronies Parishes Townlands Newspapers There are 41 primary schools currently in operation in County Fermanagh, 10 secondary schools, one special school and one further education college. Primary Schools Secondary Schools Further Education College Special School Closed Schools Fermanagh GAA has never won
3312-413: The 2011 census (ignoring Belfast and Derry City which have their own separate categories), namely; Large towns, Medium towns, Small towns, Intermediate settlements, Villages and Small villages or hamlets. The majority of the settlements in County Fermanagh lie within the final category, five within the village category and one each in the intermediate settlements and medium towns categories. No settlements in
3404-604: The Reyfad Group, the cavers' collective responsible for exploring the Reyfad system. The entrance was made in a shakehole adjacent to the sink point of the Hune (pronounced "honey") stream, and close the border in County Cavan. This entrance became known as "Pollahune". The initial route was dug through a highly unstable area of glacial fill, making it extremely treacherous. Once in the cave
3496-507: The San Agustín and Sistema Huautla caves in Mexico to decrease the weight for dry sections and vertical passages. Stage cylinders are cylinders which are used to provide gas for a portion of the penetration. They may be deposited on the bottom at the guideline on preparation dives, to be picked up for use during the main dive, or may be carried by the divers and dropped off at the line during
3588-465: The UK without a railway service. The county was administered by Fermanagh County Council from 1899 until the abolition of county councils in Northern Ireland in 1973. With the creation of Northern Ireland's district councils, Fermanagh District Council became the only one of the 26 that contained all of the county from which it derived its name. After the re-organisation of local government in 2015, Fermanagh
3680-538: The United States are more closely associated with recreational scuba diving . Compared to caving and scuba diving, there are relatively few practitioners of cave-diving. This is due in part to the specialized equipment and skill sets required, and in part because of the high potential risks due to the specific environment. Despite these risks, water-filled caves attract scuba divers, cavers , and speleologists due to their often unexplored nature, and present divers with
3772-513: The borders of the district were very similar to those of the traditional County Fermanagh, was 63,585. Of these: Agriculture and tourism are two of the most important industries in Fermanagh. The main types of farming in the area are beef, dairy, sheep, pigs and some poultry. Most of the agricultural land is used as grassland for grazing and silage or hay rather than for other crops. The waterways are extensively used by cabin cruisers, other small pleasure craft and anglers. The main town of Fermanagh
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3864-404: The buddy may know where the line is, and can be asked, and if the diver is separated from their buddy, the buddy may be at the line, and the buddy's light may be visible. Stabilising the position is generally done by finding the nearest feasible tie-off point and securely tying off a search line. The direction of the guide line when last seen should be known, and therefore the direction the diver
3956-703: The cave along the dive route will constrain decompression depths, and gas mixtures and decompression schedules can be tailored to take this into account. Most open-water diving skills apply to cave-diving, and there are additional skills specific to the environment, and to the chosen equipment configuration. The essential cave-diving procedure is navigation using a guide line. This includes laying and marking line, following line and interpreting line markers, avoiding entanglement, recovering from entanglement, maintaining and repairing line, finding lost line, jumping gaps, and recovering line, any of which may need to be done in zero visibility, total darkness, tight confined spaces or
4048-683: The cave being quite unstable, especially the JCP passage. While the location of the entrance to the cave is in County Fermanagh , the majority of the cave lies under County Cavan . The original entrance to the cave was in Cavan; however, this is now inaccessible. The current entrance of Polltullyard is located north of the Marlbank area of Fermanagh, high in the moors. The cave was discovered in August 1980 by members of
4140-574: The cave line, measurements of height, width, depth, and slope at intervals along the line, generally using a permanent guide line as a reference baseline , and take photographic records of features and objects of interest. Data are collected on wet-notes and by digital photography. Hand-held sonar may be used for distance measurement where available. Where the depth or other constraints prevent divers from exploring in person, tethered and untethered remotely operated underwater vehicles (ROUVs) have been used effectively, using sonar technology to scan and map
4232-467: The cave-diving community. In the very rare cases of exceptions to this rule there have typically been unusual circumstances. Most cave divers recognize five general rules or contributing factors for safe cave-diving, which were popularized, adapted and became generally accepted from Sheck Exley 's 1979 publication Basic Cave Diving: A Blueprint for Survival . In this book, Exley included accounts of actual cave-diving accidents, and followed each one with
4324-472: The cavers encountered a "main" streamway into which the Hune flowed, with the upstream section leading to "JCP Passage" and the downstream section passing another significant inlet, "Mistake Passage". By the end of August, the team had progressed past several boulder chokes and explored cave passages some 1.6 kilometres (1 mi) in length. Downstream, the team reached a terminus at a prominent boulder choke, through which they attempted to dig. In October 1980
4416-424: The choke. This began with a short stretch of passage leading to sump 4, which was then bypassed from above, leading to 450 metres (1,480 ft) of unbroken canyon passage. The extension eventually terminated at a new terminal sump. The new section was named "St. Patrick's Extension", and the canyon passage named "Paddy's Parade". The sump, number 5 in the system, was named "Long Way From Home". "Downstream of sump 4
4508-423: The contingency gas still in their primary cylinders. With a single stage drop, this means the primary cylinders will still be about half-full. Cave-diving training includes equipment selection and configuration, guideline protocols and techniques, gas management protocols, communication techniques, propulsion techniques, emergency management protocols, and psychological education. Cave diver training also stresses
4600-484: The county are classified as Large towns or Small towns. (population of 18,000 or more and under 75,000 at 2011 Census) (population of 10,000 or more and under 18,000 at 2011 Census) (population of 5,000 or more and under 10,000 at 2011 Census) (population of 2,500 or more and under 4,500 at 2011 Census) (population of 1,000 or more and under 2,500 at 2011 Census) (population of less than 1,000 at 2011 Census) Population statistics were not made available from
4692-558: The depth, or swept away by strong flow. Getting lost means separation from the continuous guide line to the exit, and not knowing the direction to the exit. Some cave divers are taught to remember the five key components with the mnemonic : " T he G ood D ivers A lways L ive " (training, guide, depth, air, light). In recent years new contributing factors were considered after reviewing accidents involving solo diving, diving with incapable dive partners, video or photography in caves, complex cave dives and cave-diving in large groups. With
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#17328524184434784-401: The discovery of a tight cross-rift intercepting a section of "Paddy's Parade" at right-angles. The dry, tightly meandering rift, the "Snake Escape", was followed for 30 metres (98 ft) to a 10-metre (33 ft) upward pitch , from the top of which led 70 metres (230 ft) of crawling passage to a number of deep pitch heads. The last of these pitches was found to take a small stream, which
4876-474: The dive profile, including decompression, is known, but the process may be iterative, involving changes to the dive profile as a consequence of the gas requirement calculation, or changes to the gas mixtures chosen. Use of calculated reserves based on planned dive profile and estimated gas consumption rates rather than an arbitrary pressure based on a fraction of the initial gas supply is sometimes referred to as rock bottom gas management. The purpose of gas planning
4968-479: The early 9th century, the Erne was considered to be the boundary of Connacht and Ulster , specifically the over-kingdom of Airgíalla . The Fir Manach proper, Tirkennedy and Magherastephana , along with Clankelly were part of the western Airgíalla group-kingdom of Uí Creamthainn with its seat at Clogher , whereas Lurg was associated with the northern Airgíalla branch of Uí Fiachrach centred at Ardstraw . Fermanagh
5060-807: The eastern part of the county, laid down during the Devonian , 400 million years ago. Much of the rest of the county's sediments are shale and limestone dating from the Carboniferous , 354 to 298 million years ago. These softer sediments have produced extensive cave systems such as the Shannon Cave , the Marble Arch Caves and the Caves of the Tullybrack and Belmore hills . The carboniferous shale exists in several counties of northwest Ireland, an area known colloquially as
5152-405: The emphasis on navigation, gas management, operating in confined spaces, and that the diver is physically constrained from direct ascent to the surface during much of the dive. As most cave-diving is done in an environment where there is no free surface with breathable air allowing an above-water exit, it is critically important to be able to find the way out before the breathing gas runs out. This
5244-464: The establishment of technical diving, the use of mixed gases—such as trimix for bottom gas, and nitrox and oxygen for decompression—reduces the margin for error. Accident analysis suggests that breathing the wrong gas for the depth or not analyzing the breathing gas properly has also led to cave-diving accidents. Cave-diving requires a variety of specialized procedures, and divers who do not correctly apply these procedures may significantly increase
5336-418: The estimated position of the line and slowly paying out search line, the diver will search visually, and in low visibility or darkness, also by feel, making arm sweeps across the expected direction of the line, while defending the head from impact with the other arm. The distance swum towards the estimated position of the lost line can be measured by the spacing and number of knots paid out on the search line. If
5428-440: The exit quicker and the diver is carried through places they have been before and can be prepared for difficult areas. Cave-diving has been perceived as one of the more deadly sports in the world. This perception may be exaggerated because the majority of divers who have died in caves have either not undergone specialized training or have had inadequate equipment for the environment. Some cave divers have suggested that cave-diving
5520-411: The gas supply is planned for the outward journey, one third is for the return journey and one third is a safety reserve. However, when diving with a buddy with a higher breathing rate or a different volume of gas, it may be necessary to set one third of the buddy's gas supply as the remaining 'third'. This means that the turn point to exit is earlier, or that the diver with the lower breathing rate carries
5612-437: The guide line indicating the direction to the exit before starting a search. The search line can be tied to the directional marker to prevent it from sliding along the line during the search. The direction for the search would depend on the layout of that part of the cave, and where the missing diver should have been in the group. The search party must consider their own safety first, regarding how much gas they can afford to use in
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#17328524184435704-412: The importance of risk management and cave conservation ethics. Most training systems offer progressive stages of education and certification. Various diver training and certification organizations offer training for cave divers, often based on the three cave zones defined by CMAS. Some organizations offer cavern diving training for recreational divers, (Zone 1). Cave diving involves significant risks, so
5796-470: The island of Ireland), but exploration is ongoing and further passage is expected to be found. The cave consists in the main of a large mainstream passage running to a terminal sump. The water flowing in the cave has been dye traced to Shannon Pot , two kilometres to the west of the terminal sump, which is the traditional source of the River Shannon . Inlets to the main passage are numerous. Some, such as
5888-522: The large "Mistake Passage" have been pushed only a short distance. Since the cave is undergoing active exploration , there remain many issues to be sorted out and the sinks for many of these inlets remains unclear. The stream passage itself is of considerable proportions in parts, but also contains many higher level fossil passages which have been deserted by the stream. The cave contains numerous calcite formations, with large amounts of helictites in places. Boulder chokes are frequent with several parts of
5980-434: The last trip into Shannon Cave. In 2007, after two years' work digging and stabilising, George's Choke was passed. The explorers reached the terminal sump, the first people to do so in twelve years. A new dig began on a balcony above the terminal sump, attempting to push a route through the boulder choke, but progress was slow and the choke proved unstable. In early 2008 a team of British cave divers were invited over to dive
6072-401: The line may be critical, and the procedure of choice will depend on what is reliably known. In all situations, the diver will attempt to stabilise the situation and avoid getting further lost, and make a thorough visual check in all directions from where they are at the time, taking into account the possibility of the line being in a line trap. If the diver has not also separated from their buddy,
6164-430: The line to the nearest exit. Temporary lines include exploration lines and jump lines. Decompression procedures may take into account that the cave diver usually follows a very rigidly constrained and precisely defined route, both into and out of the cave, and can reasonably expect to find any equipment such as drop cylinders temporarily stored along the guideline while making the exit. In some caves, changes of depth of
6256-413: The lost diver will know whether the diver chose the right direction to exit the cave. This is generally the converse situation to the lost guide line, in that the diver loses contact with their buddy or team but remains in contact with the guide line, so is not themselves lost. Their first priority is to not get lost or disorientated, and in furtherance of this aim would attach a directional line marker to
6348-438: The most recognized: Most cave-diving fatalities are due to running out of gas before reaching the exit. This is often the direct consequence of getting lost, whether the guide line is found again or not, and whether the visibility deteriorates, lights fail, or someone panics. On rare occasions equipment failure is unrecoverable, or a diver becomes inextricably trapped, seriously injured, incapacitated by using an unsuitable gas for
6440-449: The name Polltullyard, after the local townland, was adopted. The Pollahune entrance to Shannon was always dangerous, often dumping rocks on passing cavers and finally in 1995 it collapsed, making the cave inaccessible. During subsequent years attention was turned to Polltullyard, the downstream end of which lay within 60 metres (200 ft) of upstream JCP Passage, according to the surveys . Various groups of cavers attempted to dig through
6532-522: The naturally illuminated part of underwater caves, where the risk of getting lost is small, as the exit can be seen, and the equipment needed is reduced due to the limited distance to surface air. It is defined as a recreational diving activity as opposed to a technical diving activity on the grounds of low risk and basic equipment requirements. The procedures of cave-diving have much in common with procedures used for other types of penetration diving . They differ from open-water diving procedures mainly in
6624-465: The new settlement were the families of Cole, Blennerhasset, Butler, Hume, and Dunbar. Fermanagh was made into a county by a statute of Elizabeth I, but it was not until the time of the Plantation of Ulster that it was finally brought under civil government. The closure of all the lines of Great Northern Railway (Ireland) within County Fermanagh in 1957 left the county as the first non-island county in
6716-445: The open water surface may also be specified. Equipment , procedures , and the requisite skills have been developed to reduce the risk of becoming lost in a flooded cave, and consequently drowning when the breathing gas supply runs out. The equipment aspect largely involves the provision of an adequate breathing gas supply to cover reasonably foreseeable contingencies, redundant dive lights and other safety critical equipment, and
6808-399: The penetration to be retrieved on the way out. One of the high risk hazards of cave-diving is getting lost in the cave. The use of guide lines is the standard mitigation for this risk. Guide lines may be permanent or laid and recovered during the dive, using cave reels to deploy and recover the line. Permanent branch lines may be laid with a gap between the start of the branch line and
6900-410: The reach of natural daylight, as a way of distinguishing between cave and cavern diving. In this context, while artificially formed underground spaces such as mines are not generally called caves by divers, the activity of diving in them is classed as cave diving for training and certification purposes by diver training agencies Cavern diving is an arbitrarily defined, limited scope activity of diving in
6992-503: The risk to the members of their team. The cave-diving community works hard to educate the public on the risks they assume when they enter water-filled caves. Warning signs with the likenesses of the Grim Reaper have been placed just inside the openings of many popular caves in the US and Mexico, and others have been placed in nearby parking lots and local dive shops. Many cave-diving sites around
7084-414: The search fails, the diver will return to the tie off and try again in the next best guess for the direction the line may be. The diver may also choose to try a different search method. The best search method for any given situation will depend on the water conditions, the layout of the section of cave, the way the line was laid, the situational knowledge and skills of the diver, and the equipment available –
7176-511: The streamway comprises c. 450 m of fine canyon passage. ... [It] is perhaps one of the grandest sections of canyon passage in Ireland but on a striking scale. The passage is about 1–2 metres wide and ranges from 8 to 14 metres in height. There is also evidence of old high-level passage with a few rift/high level passage leads." Methodical exploration of high-level leads in St. Patrick's Extension in 2009 led to
7268-413: The sump, now named "Young, Free and Desperate". After 40 metres (130 ft) the divers emerged at the far side of the choke and made a voice connection with the dry cavers on the other side. After exploring downstream for one kilometre they returned to help dig from the other side of the choke. A connection was made a week later, after a further dive. 1,300 metres (4,300 ft) of cave was surveyed beyond
7360-457: The surface due to the cave's ceilings, and so must swim the entire way back out. The underwater navigation through the cave system may be difficult and exit routes may be at a considerable distance, requiring the diver to have sufficient breathing gas to make the journey. The dive may also be deep, resulting in potential deep diving risks. Visibility can vary from nearly unlimited to low, or non-existent, and can go from very good to very bad in
7452-417: The surroundings, and video to record the appearance. Features, artifacts, remains, and other objects of interest are recorded in situ as effectively as possible, generally by photography. Cave-diving is one of the most challenging and potentially dangerous kinds of diving and presents many hazards . Cave-diving is a form of penetration diving , meaning that in an emergency a diver cannot swim vertically to
7544-489: The team members, or each diver may carry their own, but in all cases each diver must be able to bail out onto a gas supply of their own for long enough to get to the next planned source of emergency gas. If for any reason this situation no longer applies, there is a single point of critical failure, and the risk becomes unacceptable, so the dive should be turned. Gas management also includes the blending, filling, analysing, marking, storage, and transportation of gas cylinders for
7636-537: The terminal boulder choke, but none were successful in stabilising the passage. In 2004 cavers from the Shannon Group began in earnest to attempt to re-enter the system, and initiated a new dig in the direction of Shannon Cave. By 2005 Shannon Cave had been re-entered via a very tight section of passage named the "Rebirth Canal". The cavers had regained JCP Passage, and access to the rest of the cave as far as George's Choke, which had collapsed again as reported by cavers on
7728-577: The type of entrance. In some caves the water surface is in view of GPS satellites, in others it is a considerable distance along a complex route from the nearest open air. Three dimensional models of varying accuracy and detail can be created by processing measurements collected by whatever methods were available. These can be used in virtual reality models. The usual methods for survey and mapping of underwater caves are dead reckoning and direct measurements of distance, compass direction and depth, by diving teams of two or three scuba divers, who record azimuth of
7820-475: The use of a continuous guideline leading the divers back out of the overhead environment . The skills and procedures include effective management of the equipment, and procedures to recover from foreseeable contingencies and emergencies, both by individual divers, and by the teams that dive together. In the United Kingdom, cave-diving developed from the locally more common activity of caving . Its origins in
7912-445: The water is clear. Caves often contain sand, mud, clay, silt, or other sediment that can further reduce underwater visibility in seconds when stirred up. Consequently, visibility is often worse during exit, and divers rely on the guideline for finding the way out. The water in caves can have strong flow . Most caves flooded to the surface at the cave mouth are either springs or siphons . Springs have out-flowing currents, where water
8004-440: The world include open-water basins, which are popular open-water diving sites. The management of these sites try to minimize the risk of untrained divers being tempted to venture inside the cave systems. With the support of the cave-diving community, many of these sites enforce a "no-lights rule" for divers who lack cave training—they may not carry any lights into the water with them. It is easy to venture into an underwater cave with
8096-702: Was a stronghold of the Maguire clan and Donn Carrach Maguire (died 1302) was the first of the chiefs of the Maguire dynasty. However, on the confiscation of lands relating to Hugh Maguire , Fermanagh was divided in a similar manner to the other five escheated counties among Scottish and English undertakers and native Irish. The baronies of Knockninny and Magheraboy were allotted to Scottish undertakers, those of Clankelly , Magherastephana and Lurg to English undertakers and those of Clanawley , Coole , and Tyrkennedy , to servitors and natives. The chief families to benefit under
8188-588: Was followed at the base of the pitch to a sump. Although it has not been traced, it is likely that this stream joins the main Shannon Cave watercourse further downstream of the Snake Escape. Upstream, beyond the pitches, a further 150 metres (490 ft) of active stream passage was followed upstream to a sump. The total surveyed length of all branches in the extension came to 635 metres (2,083 ft). A 12 minute VR documentary starring Pam and Tim Fogg based on
8280-573: Was named "The Mayfly Extension". While discoveries were being made in Shannon Cave in 1980, attention was also being paid to a large doline less than a kilometre away in County Fermanagh. Members of the Reyfad Group (including the aforementioned Rev. Pitt) and the Irish Caving Club worked together to dig their way into passage leading to a 30-metre (98 ft) underground shaft, with boulder chokes and crawls at its base. They named this cave Co-operation Pot in honour of their collaboration, but later
8372-472: Was still the only county wholly within one council area, namely Fermanagh and Omagh District Council , albeit that it constituted only a part of that entity. For the purposes of elections to the UK Parliament, the territory of Fermanagh is part of the Fermanagh and South Tyrone Parliamentary Constituency . This constituency elected Provisional IRA hunger-striker Bobby Sands as a member of parliament in
8464-520: Was swimming in before losing the line. If the diver was neutrally buoyant while following the line, the approximate depth can be reconstructed by finding the depth of neutral buoyancy again, without adjusting inflation of BCD or dry suit. Unless the line was lost by the diver not noticing a change of direction, it is likely to be at much the same depth, in much the same direction, and at a similar lateral and vertical distance as when last seen, making it logical to try that direction first. While swimming towards
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