INTRODUCTION

Diver selection up to current working depths in the North Sea (200 msw) has been predominantly determined by a process of self-selection Successful completion of training requirements, strong motivation, establishment with a diving contractor and efficient underwater performance are perhaps the essential ‘selection’ criteria used for contemporary saturation diving The safety record is at present good in the North Sea and this in itself vindicates the ‘selection’ process which has evolved through some natural form of diver attrition and ascendancy of the most competent

The future of deep (below 300 msw) diving ultimately rests in the ability of the divers to perform the tasks required by the client The move to explore and develop deeper oil and gas reserves is inevitably going to require the involvement of a freely moving independent diver in tandem with the use of RCVs, ROVs and possibly one-atmosphere divers Depths beyond 300 msw are going to place increased hazards on the diver and therefore increase the possibility of dangerous incidents occurring

The relationship between the diver and his environment becomes more hazardous as a function of the increase in depth Amplification of diver risks and diver-related problems at greater depths highlights the need for a more stringent and methodical diver-selection process How then, for example, does a diving contractor select a team of eight divers from a pool of 50 experienced and competent saturation divers for an operational dive at 400 msw?

A range of experimental dives has been carried out at various depths up to 686 m over the last decade-Deep Ex 1and 2, Physalie, Atlantis, Janus-and these have demonstrated that manned intervention can be achieved beyond the current working depths However, apart from the Janus IV series, which carried out an open-sea dive to 460 msw, and a recent Norwegian dive to 300 msw, all the dives were experimental and completed In dry, tightly controlled and relatively safe conditions There is regular diving being carried out now in Brazil to depths of 300 msw, but information regarding these dives is sparse.

Regular, operational diving with tight schedules to be met is a very different prospect to laboratory dives, and something of a quantum jump (Bentley, 1984) The effects of cold, isolation, water and anxiety are likely to amplify any problems experienced in experimental work and, in all probability, introduce more stressors than exist in artificial dives (Baddeley, 1966, Idzikowski and Baddeley, 1983)

One of the conclusions to the Deep Ex series of dives in Norway was that further research and development was necessary for operational diving at depths up to 500 msw (Tonjum, 1984) In a workshop on the long-term neurological consequences of deep diving (Shields et al, 1983) the ethical point was raised as to the safety of submitting man to ever-increasing pressures and stressors while not fully understanding the physiological and psychological effects in both the short and the long term Smith-Sivertsen (1983) was convinced that diving beyond 300 msw should be halted until diving physiology had caught up with technology and it had been proved that working beyond 300 msw was reasonably safe A structured approach to diver selection may preclude the ethical issues raised.

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