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Saturday, 2 July 2016

Running into deco

I had a conversation with a colleague in regards to his first 50 metre dive on air that entailed a small decompression obligation. Despite the depth, he was still concerned about allowing his computer slipping into required decompression stops.


He expressed concern about allowing his Galileo computer to enter such uncharted territory as PADI had always maintained a no-decompression policy. Even as a PADI instructor, he expressed concern about decompression, the PADI instructor course (IDC) teaches you to teach - not dive.

The IDC assumes you have some diving experience, although 100 dives isn't considered a whole lot of experience and a potential instructor only requires the advanced, rescue and divemaster courses - the minimum. Furthermore, the divemaster course is pretty light on dive theory as it is really a course designed to gain exposure as a teaching assistant.

At best, he would have had a few minutes at 3 metres to complete his mandatory stops. In essence, despite the depth, he spent just a short time at that 50 metre depth with the majority of his multi-level dive at significantly shallower depths.

Now I'm not stating that divers should slip into deco and dive to depths beyond the scope of recreational diving limits without the training, experience, equipment and ultimately knowledge. 

I am stating that a through knowledge of dive computers should be taught at the supervised experience course between entry level and rescue - I can't force myself to call it an advanced diver course. A higher level of knowledge is required for dive masters, assistant instructors and instructors.

What he didn't require was a decompression stop regime requiring mandatory stops at 12 metres, 9 metres, 6 metres and finally 3 metres as the fast tissue compartments controlling his dive at depth was now controlled by the medium and then slow tissue compartments as he made his way up the wall. 

I knew the dive site well as I have dived this vertical wall numerous times. I also knew the top of the wall has a depth of 6 metres so he is able to off-gas in the shallows and I bet his deco ceiling had actually resided as he ascended.

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