When one thinks about cave diving, the feelings are mixed and it is very difficult to express what it feels like in a single word, but perhaps a possible description is “to live the discovery.” Discovery is an experience and an intrinsic need in human beings since before the discovery of fire.

If you love scuba diving, deep dark waters, decompression procedures and mixed gas theory, you must have heard the name many times: Bret Gilliam, a revolutionary trailblazer in the dive world. Over the past few decades, he has changed the way scuba diving is practiced.

Some 80km south of Copen­hagen, about one hour’s drive, in what appears to be just some ordinary and inconspicuous farm buildings surrounded by fields out in the countryside, we find JJ-CCR—manufacturer of world-renowned closed circuit rebreathers.

In part one of this series, which appeared in issue #103, I suggested a few commandments to consider in order to ensure, as far as possible, that your technical dives are safe and successful. These were: First commandment: Prepare paperwork; Second commandment: Nominate a supervisor; Third commandment: Deploy safety divers. In this sequel, I deliver a few more tablets of stone.

Today, technical diving is well into its fourth decade. We now have better tools, technology and systems than we did in the past and we know far more about which methods, decompression strategies and gear configurations work well and which do not.

In the book Into Thin Air, journalist Jon Krakauer tells the story of five people who died near the summit of Mount Everest in 1996. Two were expedition leaders, one was a professional guide and two were their clients.