Swildon's Hole, a cave in the Mendip Hills of Somerset, England became one of the world's cradles for cave diving as well as the Birthing Pool of the C.D.G. Its exploration, which began in the early years of the 20th. Century, terminated at a pool of water, variously termed a Syphon, Trap or Sump.
Cavers in many countries have tried to pass these barriers in a variety of ways; using the simple "free dive" with a lungfull of air or by utilizing the available diving technology of the day.
Two Post Office engineers, F.G.Balcombe and J.A.Sheppard who were among the leading climbers and cavers of their era, combined their energies into solving the problem of passing the Swildon's sump. Their pioneering dive on 17.2.34. used a home-made respirator, designed by F.G.B, that incorporated part of a ladies bicycle frame. The attempt was unsuccessful but the foundation of Cave Diving in the U.K. had been laid.
In 1935 F.G.B.made enquiries with Siebe Gorman the leading diving engineers of the time. Although they could not help with light weight diving equipment, they did offer training with and the loan of Standard helmet diving gear.
A successful expedition was mounted at Wookey Hole, where the waters from Swildon's Hole eventually resurge. Exploration of the subterranean river Axe proceeded to the 7th. Chamber, a distance of 52M which was as far as the divers could physically handle their pipes and ropes.
The team returned to Swildon's Hole on 4.10.36. with Jack Sheppard's newly designed apparatus nicknamed "Jimmy". It was base fed by a football inflation pump that was coupled to a home-made dry-suit that incorporated lighting and a telephone. This was used by J.A.S. to pass sump l.
Later that year the bicycle respirator became self-contained with the addition of an oxygen cylinder. In turn F.G.B.dived solo through sump 1 and found the air chambers of Sump 2. These pioneers established the pattern of U.K. cave diving; the systematic exploration of a cave system in its phreas by diving both the resurgence and its tributaries. During the war years F.G.B. developed a self-contained closed-circuit oxygen set using mainly medical components. In the Yorkshire Dales he began the great canon of exploration, now known as the "Three Counties System" with dives at Keld Head, Goyden Pot and Alum Pot.
After W.W.2. surplus oxygen rebreather equipment became available, enthusiasm and the number of divers increased. In 1946 these enthusiasts had a meet in South Wales and whilst there formed The Cave Diving Group. Wookey Hole once more became the focus of diving activities. In addition to exploration the early divers found a lot of archaeological material. As the divers penetrated deeper into the cave the need for a depth penetration below 30ft.(9M-the safe limit of Oxygen diving), became more and more urgent, and the first attempt with an early aqualung nearly ended in tragedy.
Following this incident, the Group concentrated on the use of semi-closed circuit rebreathers with oxygen/nitrogen mixtures (Nitrox) suitable for the depth. In1960 the way on at Wookey Hole was found at a depth of 70ft. (using 60/40 02 /N2 ). Rebreathers were also used successfully in South Wales, Derbyshire and Yorkshire.
During the 60's with the abandonment of National Service there was an increase of caving activity by the post war population bulge. Readily available commercial Scuba equipment was adapted to cave diving. The process was accelerated by C.D.G's publication of "Cave Diving on Air" by Mike Boon and the formation of the Independent Cave Diving Group.
Divers began to dive deeper and further, inevitably, there were tragedies. Two great innovations were introduced in the interest of safety. Separate cylinders, each one with an independent demand valve; and the adoption of the Thirds Rule. One third "IN" one third "OUT" with one third kept as a safety reserve.
In the early days of cave diving in the U.K. there was always the hope of finding a way into the cave for the benefit of dry cavers. Amongst these must be mentioned Swildon's Hole, Stoke Lane Slocker, Ogof Ffynnon Ddu II and Little Neath River Cave.
Progress and development of equipment and techniques have always come in phases, and with this progress, although still hoping to discover dry caves,came diving of a purely exploratory nature . In this the Group have been very successful and considerable advances have been made at Wookey Hole and Cheddar Caves in Somerset.
In Derbyshire a great deal of effort has produced significant discoveries in the Peak Cavern/Speedwell Cavern system.
In S. Wales many kilometres of Daren Cilau were first trodden by Cave Divers; and the link with Elm Hole and Pwyll y Cwm was another major feat.
In the north, many dramatic discoveries have been made by divers; such as Boreham Cave, Notts Pot II and the connection between Gaping Ghyll and Ingleborough Cave and that between Gavel Pot and Pippikin Pot. Keld Head in Kingsdale has been the scene of operations over many years and the 2,000M. dive through from Kingsdale Master Cave represented a world standard. Later the dive was started from King Pot in the same cave system,a different route with a distance of 3050M.
In Ireland CDG members dived the connection between Noon's Hole and Arch Cave, and between Prod's Pot and Cascades Rising and between Polloughabo and Polbehan.
Several of the above diving epics have connected two or more caves together. This tendency to explore water filled caves has been extended abroad to such places as the Bahamas, where there are flooded ocean Blue Holes. These have been explored by British divers since the early 80's; several have been connected. The C.D.G. has made its presence felt by its members participating in virtually every International cave diving expedition, often using or pioneering mixed gas diving as well as adapting the cutting edge of technology. It is our proud boast that despite being the oldest amateur diving group in the world our hearts are forever young.
Cave divers in the U.K. unlike other areas of the world, have usually been represented by cavers who wished to dive. In fact one of the prerequisites of membership is that all candidates must be known to be, or become experienced and responsible cavers. The Cave Diving Group also exists for the purpose of setting standards. The standard set is a high one, and trainees are expected to work towards qualification. The Group has recently introduced a Nitrox Qualification for fully qualified members.
The Group does not recruit members; cave diving is too demanding an activity to be contemplated by anyone other than a highly motivated individual; for those who are determined the Group tries to provide encouragement, information and training. These facilities are provided on a regional basis, Derbyshire, Northern, Somerset and Welsh sections.
A candidate for membership applies to one of the regional sections, making themselves and their experience known to members. They must be over 18 yrs. old and in good health, never having suffered from epilepsy. They must be elected by the diving members of the section.
The Group also welcomes non-diving members who wish to be associated with its activities; they receive all publications, may attend all meetings but pay a reduced subscription. Of great importance is the Group's role in publishing information about exploration by members (and others) and developments in cave diving techniques. The Group produces a quarterly Newsletter and a training Manual. A sump Index is produced for each cave diving region of the British Isles. The Newsletter, which has a particularly high reputation, is free to members and on sale to the public as are all the other publications.
For further information about regional sections, training, price of publications, apply to the National Secretary