bipolarbear
Registered
I recently completed my TDI Advanced Trimix (i.e. 'hypoxic' / 'full' Trimix) course. Sam Collett of Tech Asia was my instructor.
TDI doesn't have e-learning for the Advanced Trimix course so I was required to purchase the hard copy book. The written materials, frankly, aren't great. However, most divers who are contemplating taking a course at this level will have done enough wider reading / learning to fill in the gaps.
The course standards / procedures are listed here. There are a minimum of four dives required, two of which must be deeper than 70m.
Dive 1 was a skills dive on air to a max depth of 8m. Multiple simulated failures, lots of valve drills, and lots of practice on bottle rotation, remove/re-clip deco bottles, etc. The main difference for most incoming Trimix divers is that you'll now be dealing with 3 deco / travel gas bottles instead of two. This definitely took some getting used to for the first few dives, even though initially I was just using AL40s / 5.5L tanks. The other major skill requirement for the check dive was a 20m mask-off, regulator out swim at 6m along a line. Turns out that 20m is a long way to go without breathing when you have all the gear on. I failed this on the first go but managed to pass on the second try.
Dive 2 was to 45m on air. More valve drills, simulated failures, etc. Gases were air (backgas, 2x AL80), 32% (travel / deep deco, AL40), 50% (second deco, AL40) and 100% (shallow deco, AL40). The major challenge I found was managing balance and trim with the extra deco bottle. You had to actively manage the distribution of gas in your wing to ensure that you weren't rolling to the left when the deco tanks were full, or rolling to the right as they began to empty and become a little bit buoyant.
Dive 3 was to 75m on Trimix, with DPVs. Gases were 15/40 (backgas, 2x AL80), 25/25 (travel / deep deco, AL40), 50% (second deco, AL40) and 100% (shallow deco, AL40). Total run time was 90 mins. This was a nice dive along one of the many deep walls that Puerto Galera is known for. Deco was very pleasant up onto the reefs, and the time passed quickly even with a ~25min final stop at 6m on 100%. The DPV can be used as a bit of a crutch on that final stop to fine tune your buoyancy and trim.
Dive 4 was to 82m on Trimix, again with DPVs. Gases were 15/45 (backgas, 2x AL80), 25/25 (travel / deep deco, AL40), 50% (second deco, AL80) and 100% (shallow deco, AL40). I chose to take an AL80 of 50% on this dive as your 50% deco starts to become the limiting factor when planning deeper dives and factoring in contingencies like lost 02 bottle, lost buddy, etc. Taking the larger bottle was not a problem from a trim, balance or weighting perspective, and going forward I will take the big 50% bottle for any meaningful dives in the 80+m range. Very nice deco up the reef again, for a total run time of about 90mins.
After the last dive I sat the written exam (straightforward) and am now the proud holder of a full trimix c-card.
Given the extravagant cost of Helium these days, I don't plan on executing many dives in the hypoxic trimix range. However I am glad that I took the course. I gained proficiency in handling 3+ deco / travel tanks, making an on-the-fly gas switch on descent, and have opened up a handful of sites in the 80-100m range that I would like to see before I make the inevitable transition to CCR. My final bill for the course was around US$2,200 (split around 50/50 between course costs and the cost of fills, as I also needed to pay for my instructor's gas).
I highly recommend Tech Asia if you are diving in Puerto Galera (they have a dedicated dive boat, well-maintained rental gear (i.e. deco regs) and are fully kitted out for open circuit technical and rebreather diving). That recommendation follows for my instructor Sam, who is superb. He teaches all major TDI tech courses from Intro to Tech right through to Advanced Trimix and Advanced Wreck.
TDI doesn't have e-learning for the Advanced Trimix course so I was required to purchase the hard copy book. The written materials, frankly, aren't great. However, most divers who are contemplating taking a course at this level will have done enough wider reading / learning to fill in the gaps.
The course standards / procedures are listed here. There are a minimum of four dives required, two of which must be deeper than 70m.
Dive 1 was a skills dive on air to a max depth of 8m. Multiple simulated failures, lots of valve drills, and lots of practice on bottle rotation, remove/re-clip deco bottles, etc. The main difference for most incoming Trimix divers is that you'll now be dealing with 3 deco / travel gas bottles instead of two. This definitely took some getting used to for the first few dives, even though initially I was just using AL40s / 5.5L tanks. The other major skill requirement for the check dive was a 20m mask-off, regulator out swim at 6m along a line. Turns out that 20m is a long way to go without breathing when you have all the gear on. I failed this on the first go but managed to pass on the second try.
Dive 2 was to 45m on air. More valve drills, simulated failures, etc. Gases were air (backgas, 2x AL80), 32% (travel / deep deco, AL40), 50% (second deco, AL40) and 100% (shallow deco, AL40). The major challenge I found was managing balance and trim with the extra deco bottle. You had to actively manage the distribution of gas in your wing to ensure that you weren't rolling to the left when the deco tanks were full, or rolling to the right as they began to empty and become a little bit buoyant.
Dive 3 was to 75m on Trimix, with DPVs. Gases were 15/40 (backgas, 2x AL80), 25/25 (travel / deep deco, AL40), 50% (second deco, AL40) and 100% (shallow deco, AL40). Total run time was 90 mins. This was a nice dive along one of the many deep walls that Puerto Galera is known for. Deco was very pleasant up onto the reefs, and the time passed quickly even with a ~25min final stop at 6m on 100%. The DPV can be used as a bit of a crutch on that final stop to fine tune your buoyancy and trim.
Dive 4 was to 82m on Trimix, again with DPVs. Gases were 15/45 (backgas, 2x AL80), 25/25 (travel / deep deco, AL40), 50% (second deco, AL80) and 100% (shallow deco, AL40). I chose to take an AL80 of 50% on this dive as your 50% deco starts to become the limiting factor when planning deeper dives and factoring in contingencies like lost 02 bottle, lost buddy, etc. Taking the larger bottle was not a problem from a trim, balance or weighting perspective, and going forward I will take the big 50% bottle for any meaningful dives in the 80+m range. Very nice deco up the reef again, for a total run time of about 90mins.
After the last dive I sat the written exam (straightforward) and am now the proud holder of a full trimix c-card.
Given the extravagant cost of Helium these days, I don't plan on executing many dives in the hypoxic trimix range. However I am glad that I took the course. I gained proficiency in handling 3+ deco / travel tanks, making an on-the-fly gas switch on descent, and have opened up a handful of sites in the 80-100m range that I would like to see before I make the inevitable transition to CCR. My final bill for the course was around US$2,200 (split around 50/50 between course costs and the cost of fills, as I also needed to pay for my instructor's gas).
I highly recommend Tech Asia if you are diving in Puerto Galera (they have a dedicated dive boat, well-maintained rental gear (i.e. deco regs) and are fully kitted out for open circuit technical and rebreather diving). That recommendation follows for my instructor Sam, who is superb. He teaches all major TDI tech courses from Intro to Tech right through to Advanced Trimix and Advanced Wreck.
