Future of OC trimix

[lermontov]

I second the instructors opinion, no need to do OC mix unless you have to. The experience gained can be done at shallower depths with the right practice and you can always practice bailout ascents. I would not however stop doing OC dives at nitrox depths which many divers do.

yes second this - great advice make it realistic as possible and really put the work in with labelling and switching etc.
for future - once you get past the initial set up pain with boosters and whips etc youll love diving with helium i just finished trip with 10 x 90 min dives in the 30-35m range fro about $50 of He on CCR

 

[lermontov]

So you are not paying for the classes. Don't really care how you pulled that off, doesn't matter.

What are your plans for actually diving? You take the class so you can do dives, not just take training. Not much point in taking classes and never actually go use them after class is over. At that point who is picking up the tab?

This is where OC Trimix doesn't make sense. When the money is flowing out of your own pocket.

it also depends on his time frame to do the training on the ccr, which can take 2-3 years Ive reverted to a few dives back on OC on dives beyond mod2 simply because i have yet to complete mod3 (july) and if im on a dive trip and my mates are doing 70+ m dives on ccr theres no way im going to miss out

 

[kensuf]

I'm going to take the contrary public opinion. I personally think there's huge value in doing OC normoxic trimix before hopping on CCR.

On OC you'll get more comfortable with the real gas consumption rates incurred at deeper depths (this is important for when you need to bail out and the clock starts ticking), you'll develop skills working with multiple decompression bottles (this is important for when you're on CCR and need to bail out and start managing bottle swaps), and (in the states) you won't really break the bank (this is important for your ability to keep diving).

Generally speaking, the cost of OC trimix diving comes down to that first fill and then the top-ups. You dedicate a set of cylinders to mix and then just re-fill what you use after a dive. It's rare that a person is chewing through all of their gas on a dive -- after that first fill, top-ups tend to be in the $100-120 range (at least in Florida). Not cheap, sure, but not ball breakers either.

Additionally, there's the personal development time you'll lose when switching to CCR. Most people find they lose "a season" when they move to CCR to get back to where they were previously, but I've also noticed that people that are very comfortable working with multiple bottles adapt to the rebreather quicker.

Because most of the people I know doing deeper dives on CCR's tend to limit their depths to 240' or shallower, I'm not convinced there's any advantage of doing hypoxic on OC.

Having said all that, there are significant advantages to diving a CCR over OC (problem solving time, warm moist gas which aids decompression, re-load time between dives are just three), but I personally find that the people that come to a CCR program with significant OC tech experience (including multiple bottle handling) tend to do better with the transition to rebreathers.

 

[Minion_Diver]

I did AN/DP Helitrox OC the beginning of last year and by the end of the year I had completed AN/DP Helitrox on CCR. With how expensive helium is in the Great Lakes region (well over $3/cuft) it made sense to do the switch, especially with my wife as my primary dive buddy. Fill cost racks of fast with two people diving trimix. I also like the flexibility of the CCR as well. Last year we went out on a charter and had gas for a 160' wreck and go blown off and ended up on a wreck around 100', and was tough knowing that we are wasting expensive gas. With a CCR it is no big deal to change it up like that.

 

[rddvet]

I take tech 1 in June but have been diving ccr 3 years now. I’m with Ken in that the oc training will benefit my ccr diving.

 

[kensuf]

As an added note, the cost delta between topping up from an OC helitrox dive (150', 21/35) vs an OC normoxic dive (200', 18/45) is only $10-15.

 

[Marie13]

As an added note, the cost delta between topping up from an OC helitrox dive (150', 21/35) vs an OC normoxic dive (200', 18/45) is only $10-15.

As I’ve said before you FL folks are fortunate in your He costs.

 

[kensuf]

100 cubic feet of 21/35 vs 100 cubic feet of 18/45 = 10 cubic feet of helium. Even at $3/ft you're talking $30.

 

[Divin'Papaw]

I completed TDI OC normoxic trimix in 2017 as it was a goal that I had. I'm glad I did. However, I've done very little trimix diving since.

Considering logistics, cost, and risk, diving trimix depths these days really warrants a CCR, especially if you will be doing it with any regularity. If I were younger, starting my training path today, and planned to get into technical diving seriously, I'd absolutely go CCR. At what point in your training you make your jump is the only question. Others far more knowledgeable than I have already commented above. If it were me, I'd do it BEFORE I moved to trimix. Whether to switch before or after AN/DP is a tougher question but I'd lean on after. There are many skills you learn and master at the AN/DP level that are relevant to Trimix CCR.

 

[Whitrzac]

I completed TDI OC normoxic trimix in 2017 as it was a goal that I had. I'm glad I did. However, I've done very little trimix diving since.

Considering logistics, cost, and risk, diving trimix depths these days really warrants a CCR, especially if you will be doing it with any regularity. If I were younger, starting my training path today, and planned to get into technical diving seriously, I'd absolutely go CCR. At what point in your training you make your jump is the only question. Others far more knowledgeable than I have already commented above. If it were me, I'd do it BEFORE I moved to trimix. Whether to switch before or after AN/DP is a tougher question but I'd lean on after. There are many skills you learn and master at the AN/DP level that are relevant to Trimix CCR.

You learn/master those same skills on a CCR...