Is it worth to do OC trimix before CCR Helitrox?

[J-Vo]

1) I don't think that someone's first class on the loop should involve deco. There just is a lot of new stuff, no matter how much OC experience you have. I don't think that people should do CCR deco until they have a few hours after training. I understand that some agencies may think otherwise.

Sure it wasn't CO2?

I'm not an expert or an instructor, but I like that this is at the instructors discretion.

I came in to MOD1 with around 50 hypoxic OC dives logged post training. After 7 days of CCR Hilitrox class I felt my CCR buoyancy was better than my OC. My instructor had no problem giving me the Hilitrox CCR cert. I'm sure some don't get there by the end of the week.

 

[doctormike]

I'm not an expert or an instructor, but I like that this is at the instructors discretion.

I came in to MOD1 with around 50 hypoxic OC dives logged post training. After 7 days of CCR Hilitrox class I felt my CCR buoyancy was better than my OC. My instructor had no problem giving me the Hilitrox CCR cert. I'm sure some don't get there by the end of the week.

I'm not an expert or an instructor either. And clearly people with far more qualifications than me feel otherwise.

But I will say this. The most dangerous time on CCR is said to be around 100 hours after training, when you feel dialed in and comfortable, but may not have had experience with a real life gear failure or other accident.

So of course, you were able to pick up buoyancy quickly, within the confines of a course. And if you are an experienced trimix diver, then the academics of CCR helitrox are probably easy for you. Getting through a class is different from your first real world disaster, but I would of course defer to your instructor.

But I still think that new CCR divers should put some time on the loop before doing more advanced dives. The devil is in the details. I guess if GUE considers 50 feet a trimix mandatory dive, then helium wouldn't be the dividing line between basic and advanced in that world. Maybe I'm not explaining this well. But I think you know what I mean...

 

[J-Vo]

But I will say this. The most dangerous time on CCR is said to be around 100 hours after training, when you feel dialed in and comfortable, but may not have had experience with a real life gear failure or other accident.

Agreed.

At around 150 hours I still don't think it has fully tried to kill me. I've had a dilout boom, a partial flood, and run out of O2, but have yet to feel I had to come off the loop.

 

[broncobowsher]

I find Helium more beneficial in CCR than OC. That being I will go deeper without Helium on OC than I will on CCR. I forget the details that were given to me in my Normoxic class, but there are reasons why CCR gets more Helium and gets it shallower than OC. Cost wasn't it, something physical.

 

[Wibble]

But I will say this. The most dangerous time on CCR is said to be around 100 hours after training, when you feel dialed in and comfortable, but may not have had experience with a real life gear failure or other accident.

Hell yes. But you learn an awful lot from that event and consequential bailout though!

 

[BlueTrin]

So just for info, there was a bit of a plot twist here: if I do the training in the UK (which is likely I will do), the instructors I wanted to train with did not want to do Helitrox because that would require a 40m dive and since the NDAC (National Diving & Activity Centre) has closed, there is no backup option in case the weather is not favourable.

So I will most likely end up doing ANDP then Trimix later on rather than Helitrox first.

EDIT: actually there is a double twist, I asked and since the other student is interested as well, we will go with an option for an extra day in case the weather is favourable and try for Helitrox if possible, weather permitting.

 

[Gareth J]

When I first crossed over from OC diving to CC diving, I was qualified as an OC Trimix diver, unlimited depth, any mix.
The first 12 months after receiving my unit, none of my diving was over 30m. Mostly, I was diving with OC divers, so, even though my dive didn't require a stop, I was running long stops with my OC buddies.
CC diving is very different to OC diving, you need to break a large number of OC habits which are not compatible with CC diving. It was over a season before I did a mix gas crossover to the CCR. (In truth, I could have dived Trimix on the unit with ease, I was the blender at a shop and had my own gas at home. I was very aware of the number of deaths of very experienced OC divers who had transitioned to CCR and immediately returned to deep diving. I did not want to join that statistic.

I mainly dive CCR, the only time I dive OC is teaching, or if I have a unit failure.

Whilst normally I would strongly recommend divers doing advanced qualifications do them in the environment they dive. e.g. Trimix course in UK offshore waters if diving deep wrecks in the UK.
For CCR, because I had hours of UK diving under my belt, I opted to learn in slightly warmer waters. For the Basic course I did it in Lanzarote, not the warmest place, but far warmer than the UK in February. Similarly, the Trimix crossover I did in the Red Sea.
The reason for this was simple, time on a unit is important, long dives, running through lots of exercises. When I did my course in Lanzarote, myself and my buddy actually did twice the hours of any another student with our instructor. Similarly, the trimix crossover, I wanted as many hours as possible in the water. The Red Sea ensured, cold, weather or tide wouldn't limit our dive times.

Whilst you can take OC experience into CC diving. A lot of the basic theory is similar, END, MOD gas calculation, etc. There are aspects of CCR diving that are not the same.

 

[GF99/99]

I am thinking of getting CCR trained while having only TDI ANDP.

I hear all the time that it is worth getting OC Trimix trained before CCR in case you bail out.

What are your opinions on this?

My personal opinion is skip OC trimix. The cost and logistics of OC trimix fills is not worth it. Now that being said I think having solid OC skills (if your ANDP defiantly take the extended range course) if a major benefit that furthers your diving knowledge and skills but this does not mean you need to do OC trimix.

I went down the OC route all the way through Adv. Trimix then switch over to CC worked my way through mod 3 and never looked back. I pretty much never dive OC except for the occasional dive on the twinset just for the fun of it or for cave.

Unless you live somewhere that has ridiculously cheep helium or you are just really rich I highly doubt you will ever dive OC trimix if you do the course and then switch over to CC.

 

[BoltSnap]

I went down the OC route all the way through Adv. Trimix then switch over to CC worked my way through mod 3 and never looked back. I pretty much never dive OC except for the occasional dive on the twinset just for the fun of it or for cave.

Is this simply because of the savings on He when using CCr or are there more practical reasons?

 

[DS79]

I am thinking of getting CCR trained while having only TDI ANDP.

I hear all the time that it is worth getting OC Trimix trained before CCR in case you bail out.

What are your opinions on this?

Nowadays (he prices), I would definitely
save the money and time and skip OC TX courses. There is no big miracle about brething a helium mix in general and theoretical and practical knowledge of that is not different from breathing it OC and CC.
However, I personally benefited a lot from hundreds of gas-switch dives (Bottom gas - mainly air to deco gases), before I actually got into rebreather diving.
So I guess, having done a deco procedures/ adv. nitrox course and being used to juggling around with stages, gas switches
etc. is helping a lot to have some BO routine.