Introduction
With the tragic death of Cave diver Alan Clegg in the downstream sump of Lancaster Hole at Easter 1964, the Northern Section of the Cave Diving Group had for the most part become inactive with only three members still diving, Mike Boon, Pete Livesey and Ken Pearce.
During this period a number of capable divers from the Somerset Section of the CDG carried out some very successful dives in northern caves. Amongst these divers were Dave Drew, Dave Savage and Mike Wooding.

During the latter part of 1965 a small group of northern cavers with an interest in cave diving came together and once again began operating as a group. These cavers came mainly from The Bradford Pothole Club and The Happy Wanderers Cave and Pothole Club. They worked together as a team and began a series of dives in Langstroth Cave Upper Wharfedale in an attempt to scale the 14metre high aven.*

Throughout the previous year many of the cavers had been dive training at Keighley Sub Aqua Club. These sessions took the form of swimming pool training followed by a lecture on the physiology of diving held in the Cavendish Pub, Cavendish Street Keighley. Most of the group attained their BSAC accreditation at these sessions. Regular attendees were Bob Jarman and Bob Gillibrand and until his untimely death Alan Clegg. The Keighley branch of BSAC was especially easy-going allowing these divers to use a rudimentary homemade rebreathing set.  

Early in 1966 a decision was made to reform the Northern Section of the Cave Diving Group, a division of the Cave Diving Group based in Somerset.
On January 22nd 1966 fifteen interested cavers attended the inaugural meeting of the Northern Section of the CDG held at the BSA H.Q. Duke Street, Settle.  At the meeting Ken Pearce was elected diving officer and Mick Melvin secretary of the Section.

During the next 18 months the Section carried out many cave dives, and then tragically the activities largely came to a stop in June 1967 with the Mossdale tragedy.
This disaster that took the lives of six experienced cavers, robbed the Section of two of its most active divers Bill Frakes and John Ogden. In the previous 18 months together with Dave Stewart and John Southworth, these two divers had been responsible for many of the Section’s successes.
During the period January 1966 to June 1967 Dave Stewart kept a written logbook of the dives carried out by the Northern Section of the CDG and up to the present time this logbook has never been published.  The logbook has now been digitised and its entire content is available here.

The Diving equipment
In the early sixties Mike Boon produced and built a breathing set for use in cave diving operations and he gave it the name 'Niphargus'. The apparatus consisted of a 750 litre cylinder of air compressed to 122 bar carried on the side of the body by a harness of web strapping with air being fed to the diver by means of a split stage ‘Scubair’ demand valve i.e. single hose two stage reduction.
Together with the lead weights slung around the waist and a miner's cap lamp for lighting this B.A. was a very compact item of equipment and, with minor modification, was the apparatus being used by members of the Northern Section of CDG throughout this period.

*A Cave Dive with Bill Frakes: Page 10 ‘Langstroth Cave 1965’.
Although not originally part of Dave’s logbook, he feels that this article by should be included for completeness.