One of (if not the) most contentious aspects of diver training is deep air diving. Despite the best efforts of the major technical diving agencies and instructors to promote and educate divers in the use of other breathing gases to increase their safety at depth, the truth is that the vast majority of dives conducted below 40 metres are carried out on air. Weekend after weekend divers who have had no real formal training in deep diving skills take to the water and head off down into the depths. Most of these dives are conducted on the basis of 'we'll start to come up when the computer gives us 5 minutes' or 'when we get to 50 bar we'll head up'! Very rarely do we see divers sit down and, as a team, plan out the dive to take into account air consumption, run times, bail out scenarios etc. For most divers a 40-50m dive is safe - until it isn't!

Like a number of other US training agencies the PSA (Professional Scuba Association) have been running deep air and extended range training courses in the US since the mid 1980's and recently UK instructor Mark Andrews of Sovereign Divers took a course with the PSA in teaching their method of extended range diving. I sat in on a level II course that teaches divers how to conduct air dives safely down to a maximum of 40m. Many will argue that '40m isn't deep' or that 'you can't teach me anything, that's the sort of diving I'm doing already'. The simple truth however is that unless you have undertaken some form of extended range or technical diving training course, things like gas management, equipment configuration and ascent/descent procedures will not have been learned.

The training began with a course overview and an insight into who PSA are. In 1987 the legendary American diver Hal Watts established PSA at the famous 'Forty Fathom Grotto'. Watts has held and set many deep diving records in his time and has trained six other divers (including his daughter) who have gone on to achieve record depths. It was Hal who coined the phrase 'plan your dive - dive your plan' and all of PSA's teaching has this philosophy at its heart. The first day is taken up with the bulk of the theory side of the course. Running through equipment requirements, safety guidelines, deep dive planning and the theoretical and physiological concepts of deep diving really had the students beginning to get their heads around what the reality of deep diving is all about. Both students were PADI divemasters and although they had both dived to 40m in clear warm water, this was their first time in the UK. They both felt that a 40m narcosis level would be more than manageable - they were in for a shock.

With the theory completed it was time for the first of the practical open water sessions. Prior to the first dive Mark examined the students' diving rig which was the standard 15li cylinder, main valve & octopus and stab jacket. Discussing the kit Mark tried to get the students to understand the limitations of their own equipment and configuration rather than simply rubbishing the set up. The first dive was very much a shake down session where Mark got to assess his students in the water, watching. This was followed by a de-brief where once again the students began to take a critical look at the way they were currently diving. They then had the time to re-assess and set up their own equipment before the final dive and assessment.
For the final dive the students had set a run time of 15mins @ 40 metres. Swimming out to the buoy the divers began their descent down the shotline, which dropped to 48 metres. PSA teach that the descent phase of the dive should be broken down into two sections. Firstly the divers drop to what they have decided will be a 'level off depth' where they assess each other's faculties and check buoyancy before finally descending to their target depth. The students then had to carry out a number of skills including gas monitoring, narcosis assessment and equipment drills.

During the bottom phase PSA encourages divers to keep their swimming movements to an absolute minimum in order to cut down on exertion and so keep down narcosis. Discussing this aspect of the training with Mark later I stated that I thought that this was one area where PSA's logic does not apply to British waters. Whilst I agree with the theory behind the teaching, it is one thing to drift motionless along a reef in clear blue water, but over here we tend to be working in lower visibility and stronger tidal streams - conditions not really conducive to minimal movement.

For the ascent, PSA recommends that the diver uses their BC or wing to bring themselves up at a controlled 10 metres a minute. The idea is that (a) because the diver isn't swimming up they aren't exerting themselves so narcosis levels and gas consumption are reduced, and (b) that if the diver has a problem during the ascent, it is better to have positive buoyancy rather than negative. The students found this phase of the exercise to be the most difficult. Having left the bottom bang on 15 minutes, they arrived at their first stop (6 metres) at 20 minutes. The students found that for most of the ascent they either over inflated or dumped too much air so their buoyancy was all over the place.

Topside once more the divers ran through how they felt the dive had gone. Mark quizzed them both on certain aspects such as objects he had asked them to remember and questions on gas consumption, trying to assess just how much they had been affected by narcosis. Both the students stated that they had felt well and truly narked on the bottom and had struggled to achieve the tasks. Mark pointed out that the extra task loading probably added to their narcosis and that with time and practise these essential skills would become second nature and be effortlessly incorporated into their dive routine.

At the end of the course both the students agreed that they needed a lot more practice and experience in the 30-40m zone before they thought about going deeper (PSA run courses to teach deep air diving down to 70m - but that's another story!). My thoughts on the course were that there are a heck of a lot of divers out there who don't want to buy a twinset, high volume wing and embark on 'techie' dive training, but who would vastly benefit from doing a course where they sit down and take a reality check on safety and survival in the sub 30 metre zone.

For details of PSA training contact Mark
Andrews at Sovereign Diver Tel: 0961 552767
E-mail: extreme@deepdiving.freeserve.co.uk

By Ron Mahoney.