What is Deep Diving?

“After my first 10 hours on a rebreather, I was a real expert. Another 40 hours of dive time later, I considered myself a novice. When I completed about 100 hours of rebreather diving, I realized I was only just a beginner.” — Richard Pyle, reflecting on the steep learning curve of rebreather diving blog.padi.com

When diving, everything is interconnected, and the plan must form a coherent whole. It is therefore essential to establish a clear starting point. Naturally, the starting values are depth and bottom time. We generally dive to different depths for varying lengths of time. While we usually have a clear idea of the intended depth, determining bottom time is not always simple, as it is often limited by available gas supply and the required decompression obligation. Sometimes we must use the method of halving the interval, choosing a bottom time that fits within our gas reserves. When we talk about gas supply in closed-circuit diving, we mostly mean bailout gas. Especially for beginners, it is not assumed that dives will be carried out at the limits of rebreather gas capacity. The simplest scenario, of course, is when we have a very specific bottom time required to achieve our goal.