Open water certified scuba divers are allowed to dive to a maximum of 18 metres but this limitation becomes very tiresome early in our diving career. The old saying about faraway hills being greener applies in a slightly different way underwater, with the deep blue holding a great pull for most scuba divers. One of the most interesting specialities offered by PADI is the Deep Diver Specialty Course and a deep dive is also a requirement of the PADI Advanced Open Water Diver programme.
Forget the boss, I'd been working hard for the last 6 months and deserved a break so I was off to South East Asia where cold and rain would be a distant memory, for a while at least. 2 weeks on holiday diving in Thailand would allow the chance for many different adventures but I was determined to make an effort to increase my knowledge of scuba diving and clock up a few new experiences in my log book. I reviewed the list of PADI speciality courses and decided that Deep Diving would be my next scuba experience. Many of my friends had told me about the onshore action to be enjoyed on Phuket Island but, as few of them are divers, I was not sure what to expect underwater.
The little I knew in advance about going deeper was from other divers who referred frequently to the effects of being "narced" while on those portions of the dive from which I, as an Open Water Diver, was excluded. On further inquiry I found out that one of the biggest additional factors to consider, for the recreational deep diver, is the effects of nitrogen narcosis. This phenomenon can cause the diver to experience a sense of euphoria and diminished psychological stress and can result in inappropriate behaviour and the abandonment of normal caution. The experience is often referred to as the "Martini effect" being, in some cases, similar to the feeling of consuming alcohol.
What could be better, thought I, experience the wonders of the underwater world and have a couple of Martini's along the way. Given the option my tipple of choice is a pint of Guinness but in a pinch I would not refuse a Martini. The course itself involves a number of deep dives plus the theory element we have become familiar with on all PADI courses. The aim of the dives is to highlight the effect of the deep water on the diver and the experience of the underwater environment. Colours disappear gradually as you descend and any flexible container will reduce considerably in size, only to expand again as the diver ascends to shallower depths and reduced pressure. The most surprising and interesting effect is on the ability of the diver to concentrate at depth.
The required dives took place at 2 different locations off the west coast of Thailand. The King Cruiser Wreck a Phuket dive site was the site of the mental challenges and I chose to ignore the comment regarding the extent to which I was challenged by this portion of the course. On this very popular site I was also asked, by the instructor, to lead the group for a portion of the dive. The route was carefully planned at the surface and I was scheduled to relinquish my leadership at a smoke stack on the main deck of this large wreck. I was feeling very pleased with myself as I negotiated the way along the predestined dive path but my confidence began to evaporate when the objective landmark failed to materialise. If anyone knows the hand signal for "where the bloody hell is the smoke stack?" please let me know. At the surface the instructor explained that the stack had collapsed since his last dive on the wreck a week previously, a reminder that all wrecks are in a constant state of change and decay.
The second location for the course took place among the internationally famous Similan Islands and I was so taken by the quality of the diving here that I cannot remember the specifics of the course requirements. Looking back at my dive log it makes detailed reference to sharks and mantas and in passing notes that the objective of these dives were related to the completion of my course. I'm glad that I now had my Deep Diving qualification as otherwise I would not have been able to fully appreciate the wonders of the Similans. On my many subsequent visits I have now discovered why the Similans are regarded among the best diving destinations in the world.
On completion of the course I was now certified to dive to 40 metres (the maximum limit for recreational divers) and will no longer be left behind when the rest of the group goes deep. A great deal of new diving opportunities has been opened up and in my opinion this is one of the best specialities offered by PADI. On a more serious note, one also gains a much better understanding of the forces we experience when we dive and their effect on our system. This greater knowledge leads to better enjoyment of the sport we all love, scuba diving.
The Deep Diver Specialty, qualifying you to a depth rating of 40m, is one of the PADI courses that gives the instructor the most satisfaction in teaching. There are several reasons for this. Firstly, students taking this course are expressing a desire to extend their training and experience beyond that of most recreational divers, and it's always great teaching divers that have been bitten by the diving bug and want to learn more.
Secondly, instructors themselves also get a lot of satisfaction out of diving deep, with the chance to see something unusual, particularly if they work in a resort environment, teaching beginners all the time. The best thing about diving deep is that you can see stuff that you won't normally see, including Sharks and Rays. If you take your course at a location that has good deep dive sites, like Similan Islands or Racha Noi, chances are you'll have some "firsts" in your log book.
There are a number of significant factors to consider in conducting deep dives, all which require extra caution. Firstly, your students are going to get through their air a lot quicker - 5 times faster at 40m depth, than at the surface - so you must ensure that they and you are more watchful of the air reserves. If you run out of air at 40m, a controlled emergency swimming ascent that you learned on your Open Water Diver Course will not get you very far.
Secondly, nitrogen narcosis - Jacques Cousteau's Rapture Of The Deep - will play a significant part. There's no escape and you must be vigilant to its effects. Instructors are not exempt either - I remember well an occasion diving in Mozambique when I took my regulator out of my mouth to try to read my air gauge! I myself am quite easily affected by it, especially in poor visibility (I think it's disorientation that can trigger the effects for me), and students must have the maturity to accept defeat and ascend shallower when under the influence.
Thirdly, students must understand that, maybe for the first time, they will need to ascend to end their dive before they run low on air. This is because the controlling factor on a deep dive is not your air supply, but the build up of nitrogen in your blood. Students must have their own dive watch, or better still, dive computer.
Other factors that can be important are changes in temperature at depth, visibility and currents. These may be no less significant. One deep dive I made on the Transvaaler Wreck in Cape Town, resulted in an "Advanced Diver" running out of air at the bottom of the descent after 6 minutes - not good fun! He had never dived in waters so cold before and it quite literally took his breath away.
The student performance requirements of each dive on this course are not so demanding. But is the participation in and experience gained from 4 dedicated deep dives under the direct supervision and safety of an instructor that is vital to the student.
Once you've completed this course, you'll find that you've opened a whole host of new dive opportunities that would have been closed to you before, and you can make the most out of most dive sites - at all depths - that you will visit in the future.
Please note, you must hold at least an Adventure Diver Certification to participate in this PADI dive course.