On open circuit, decompression is about managing your gas supply against your deco obligation. On CCR it's about managing your setpoint to optimise the decompression while staying on the unit. Different problem, different tools, vastly better results when done right.
One of the things that often surprises open-circuit divers converting to CCR is that rebreather decompression works differently from what they're used to — and in many ways better, if you understand how to manage it. On CCR, you have continuous control over your oxygen partial pressure throughout the ascent. You can hold a high setpoint during your deco stops, accelerating inert gas off-gassing. You can optimise your decompression in real time based on what the unit is doing. It's genuinely powerful — and genuinely requires proper training to do safely.
The TDI CCR Decompression Procedures course covers planned staged decompression on a closed-circuit rebreather to 45 metres. We're specifically looking at how the rebreather changes the decompression picture compared to open circuit: setpoint selection during ascent, optimising stops with elevated PO2, managing the deco schedule when the unit behaves unexpectedly, and how bailout procedures interact with a decompression obligation.
The last point is one I want to be direct about: a bailout from a CCR dive with a significant decompression obligation is a complex situation that requires pre-planned procedures and sufficient bailout gas. At 45m with a meaningful bottom time, your bailout requirements are substantial. We work through the planning for this in detail, because the consequences of insufficient bailout gas during a deco emergency on a rebreather are severe.
Malta's wrecks at the 30–45m range are excellent training grounds for this course. The MV Karwela at 43m gives you a proper decompression dive on a genuinely interesting wreck. Le Polynesien deeper down shows you what you're training toward. The visibility means you can actually see your handsets, your stops, and your team — which makes the learning process significantly better than murky northern European water.
3–4 days is the minimum for this course and it doesn't feel like padding. Decompression planning at this level, combined with CCR-specific considerations, takes time to develop properly. We'll work through it until it genuinely clicks — that's what the time is for.
This course can be run in combination with CCR Mixed Gas / Helitrox for divers who want to approach decompression diving at greater depth from the start. Talk to me about sequencing if that's your direction.
CCR Decompression Procedures is the foundation for all serious CCR diving. Once you can plan and execute staged decompression on the unit, the combination with helium diluent (from the Mixed Gas course) opens up everything Malta has at depth — including HMS Olympus at 90m, which is one of the extraordinary dives of the world, no hyperbole.