TDI · Poseidon rebreather
TDI Air Diluent CCR Decompression: Poseidon Se7en
Planned decompression on the Poseidon, to 40 m with an air diluent.
On a rebreather, decompression is a different experience. You hold the best possible oxygen partial pressure the whole way up, gas use hardly changes with depth or stop time, and a long hang is warm and quiet rather than a cold count of cylinder pressure.
This course adds formal decompression to your rebreather diving, to 40 m on an air diluent. You'll plan it, bail out from it, and learn the discipline that makes it routine.
- Minimum age
- 18
- Two ways in
- Upgrade from Air Diluent CCR, or come straight from open circuit
- Duration
- At least 5 days (fewer for upgrades)
- In-water time
- 420 min over 7 or more dives; 240 min for upgrades
- Maximum depth
- 40 m
- Ratio
- At most 3 students per instructor
Prerequisites
- Minimum age 18.
- Either: TDI Air Diluent CCR Diver (or equivalent), with at least 30 hours over 30 dives on the unit and 6 months of CCR diving.
- Or, straight from open circuit: TDI Advanced Nitrox and Decompression Procedures (or equivalent), 50 logged dives, and at least 5 logged staged decompression dives to 30 m or deeper.
What you'll learn
- Planning CCR decompression: setpoints, bailout gas and bailout decompression schedules
- Carrying and managing bailout cylinders
- Running stops on the loop, and handling problems during decompression
- Bailing out mid-decompression, and still getting everyone home
- Before the open water dives: a 50 m surface tow of a fully equipped CCR diver
- Training dives carry up to 10 minutes of decompression, with at most two decompression dives a day
What you'll need
- Your Poseidon Se7en or MkVI Discovery. Hire is available, but owning your own is strongly recommended
- Bailout cylinder(s) and regulators sized for a bailout ascent from the planned dive
- Ascent reel and SMB, cutting tool, exposure protection for long stops
Already a Poseidon Air Diluent diver?
Once you have 30 hours over 30 dives on your unit and 6 months of CCR experience, you can upgrade. That's a skills evaluation dive plus at least 4 open water dives, 2 of them deeper than 30 m, for 240 minutes in the water in total.
Where it leads
- Poseidon Se7en Helitrox CCR (45 m): Helitrox: add helium to the diluent, and go to 45 m
Why learn it with me
This is the course where a rebreather stops being a novelty and becomes your main way of diving. I keep groups small, three at most and often just you, because decompression on a CCR is learned by doing it well, repeatedly.
Course limits and prerequisites follow TDI Standards & Procedures, Part 2 (v0126), section 31. Standards change, so I'll confirm them when you book.
Interested?
Tell me your certifications and roughly how many dives you've logged, and I'll confirm you're ready.