Recreational Trimix Course

[LKunze]

I've noticed that one of the certification agencies (I believe IANTD) is going to be offering a "Recreational Trimix" course. It allows recreational divers to use 30/30 trimix down to 130 feet, PO2 no higher than 1.5 and they must be no-deco dives. The only prerequiste is Basic Nitrox certification. This interests me quite a bit for the dives in the 100 - 130 foot range. Just thought I'd pass it on.

[tcjtn0]

Only basic nitrox reqired for this Rec Tri-mix??? Seems kind of strange to see tri-mix and the work Recreational used in the same line...

Jean

[LKunze]

I think it's kinda cool myself that recreational divers will get the benefits of using trimix too without having to take the full blown technical trimix course which is real spendy along with all the extra gear required for "tech diving". It's not like I'd be going out and getting my tanks filled with 30/30 all the time but for trips to Superior, etc. it would be great being able to dive with a clear head and remember more of what I just saw on the deeper dives.

[Freedive WI]

LKUNZE,

Where did you find that info?? there is nothing onthe IANTD site about it.

I know that GUE has had a course out like this for a while. I say it's about time. If you can handle nitrox without hurting yourself than a 30/30 mix is fine- I use it all the time when I actually tank dive. A nice slow ascent is the only thing to keep in mind- which you should be doing no matter what your breathing.

IANTD now offers freedivng courses and recreational trimix, when will TDI and PADI catch up??

Jon

[LKunze]

Jon, I found out about it on Going Under Dive Center's website on the "newsletter" page.

[john j]

Why does a recreational diver (single tank, no decompression, 130ft max) need to use trimix? I've been thinking this over and I can't see any solid benefit here.

Is the narcosis really that bad at 130ft or less for someone who is only going to be there a few minutes? I can understand the benefits for long, deep technical dives but not for a single tank recreational diver who is only going to be there for 5 minutes.

What is the single tank trimix diver going to use to inflate the drysuit? Can't use the trimix. Need another cylinder I guess.

Isn't the helium going to actually shorten the no decompression limit compared to a nitrox mixture with the same PO2? I ran a few quick dive plans on v-planner last night and it was giving me longer no-decompression limits on air than I would have on trimix 30/30. So I guess there isn't any no decompression advantage. Helium mixes are very unforgiving if you ascend too fast or miss a deco stop too.

I did some searching on the net and the benefits I saw listed were less narcosis and less breathing resistance. Narcosis at 130ft isn't that bad anyway and nitrox would reduce narcosis too. As far as breathing resistance goes, if your reg has breathing problems at 130ft, then you probably ought to get something else. Nitrox would work just fine for these dives and it's a lot cheaper than trimix.

I'm not trying to flame here, just trying to figure this out. Why do we need to use trimix for single tank, no decompression dives to 130ft or less?

[LKunze]

Hmm...yeah I don't know John. I don't think anyone said you "need" to use trimix on these types of dives. I think the benefits are a clearer head and reduced Co2 retention.

Is the narcosis really that bad at 130ft or less for someone who is only going to be there a few minutes? I can understand the benefits for long, deep technical dives but not for a single tank recreational diver who is only going to be there for 5 minutes.

Well, I guess it depends on what you mean by "that bad". Narcosis effects your memory. After a deep dive...at least for me, I find that I don't remember too many details of the dive afterwards. I would like to think that eliminating the narcosis would make for a more enjoyable dive even if I'm not at depth a long time. Especially if it's diving a wreck that I won't get to go dive very often.

What is the single tank trimix diver going to use to inflate the drysuit? Can't use the trimix. Need another cylinder I guess.

That's a valid point and one I hadn't thought of but don't most drysuit divers use an argon bottle, even if it's just got air in it? It's probably a better to have a separte small 6 cu. ft. bottle for drysuit inflation anyway even if you were just diving nitrox right? I don't have an argon bottle yet but it's something I've thought of getting though.

Isn't the helium going to actually shorten the no decompression limit compared to a nitrox mixture with the same PO2? I ran a few quick dive plans on v-planner last night and it was giving me longer no-decompression limits on air than I would have on trimix 30/30. So I guess there isn't any no decompression advantage.

Hmm...given the fact that we're talking about a single tank dive with it's obvious gas limitations is that really a big issue though?

Helium mixes are very unforgiving if you ascend too fast or miss a deco stop too.

Good point but someone who can't control their buoyancy and make a slow controlled ascent shouldn't be taking the course right?

I did some searching on the net and the benefits I saw listed were less narcosis and less breathing resistance. Narcosis at 130ft isn't that bad anyway and nitrox would reduce narcosis too. As far as breathing resistance goes, if your reg has breathing problems at 130ft, then you probably ought to get something else. Nitrox would work just fine for these dives and it's a lot cheaper than trimix.

Yeah, nitrox is definately adequate, it's just the elimination of narcosis and reduced Co2 retention that will be better on trimix.

I'm not trying to flame here, just trying to figure this out. Why do we need to use trimix for single tank, no decompression dives to 130ft or less?

I wouldn't accuse you of flaming at all. You bring up some good points. It's good to get some discussion going on topics like this. Especially for non-tech divers such as myself who like to learn more about this stuff. I'd like to hear what some of the other more experienced divers on the forum have to say about this topic too. So chime in please.

[Freedive WI]

The course would be great for anyone going into a wreck who needs a super clear head. It is also a great gas for underwater photographers because you are much more aware of what you camera settings are. I think that any dive rescue team working in 80' of dirty, read zero vis, water would love it.

It is amazing how many little details you miss on dives as shallow as 80' when on air, or nitrox, compared to trimix. I wouldn't have believed it if I hadn't seen it for myself. I have been diving on a local, Lake Michigan, wreck for over 20 years. I have more dives on her than I can count. I now only freedive her because she isn't that deep- 90'. The last time I dove her, and the time before that, ect, I saw more details inside of the engine room than I had ever noticed before, because I was diving 30/30 trimix.

In the past I have dove a whole lot deeper than that on air and "thought" that I was just fine because I manged to shoot off a role of film, but I really wasn't. I believe that the navy EOD divers use heliox in their rebreathers on dives below 70'- according to the mixed gas navy dive manual. Clear head, ease of breathing, less likely to freeze a reg in cold water are all reasons for switching to this gas.


I don't know about v-plan, since I never did liked that program to begin with, but I ran the nummbers on D-plan, from GUE, and they came out to within a minute of 30% nitrox and WAY better than air.

Yes, you need a seperate inflation bottle for your suit, but since every nitrox diver I know, who dives the wrecks in Lake Michigan, is already carrying argon this isn't such a big issue.

The real advantage I can see to this course is 4-5 years down the road. I think that all deep air and advanced nitrox courses, with air/nitrox dives to 150' will be gone. People will just go from nitrox, to recreational trimix, to full-blown trimix in three easy steps. There will be less liability for the instructors, no narcosis, and safer dives for the students, no narcosis, and it will just become as accepted as nitrox is today - which WASN'T always the case!

There are a lot of misconceptions out there about this gas and this course should help to dispell those. I think it's an awesome idea. GUE might have started it, but it's great that everyone else is picking up on it. It can only make diving safer.

Jon

[john j]

I use a lot of trimix myself and probably 90% of the diving I do is on trimix, but that's because the dives are very deep or in overhead environments. At 130ft or less I would almost never use trimix unless that was all I had for some reason. I still don't see any true advantage for the recreational diver in diving trimixes at 130 feet or less on no decompression dives. Will these divers be willing to pay the relatively high cost of helium mixes for a few minutes at 130ft? I wouldn't. It also concerns me to hear you say that a diver could eventually progress from nitrox to full blown trimix in "three easy steps". If people start getting full blown trimix certifications as easy as open water or nitrox certifications, there will be accidents. I worked long and hard for my trimix certifications and in retrospect, that has probably saved my life on a few occasions. I'd rather spend the money on the advanced nitrox/deco procedures class than on some recreational trimix class that isn't going to let me spend more than a few minutes at 130ft anyway. If you learn how to deal with even mild amounts of decompression, you can significantly extend your bottom times. If there was a wreck at 120ft for example, I'd rather spend some extra time down there and have a few minutes of decompression than spend $20 or more on a trimix fill any only have a few minutes to spend on the wreck anyway. You had said one benefit of the recreational trimix course was that the diver would have a clearer head for wreck penetration, but overhead environments are beyond the scope of recreational divers anyway so this seems to be an invalid argument in this case. If you are talking technical diving, then that's different. I'm really trying to understand this recreational trimix class and I just can't. I'm hoping someone can show me something that will make it all really obvious why recreational divers need trimix. Seems to me like it's just another certification for the sake of getting another card. When I look at the actual value of the training and usefullness, it seems very weak to me.

[Skruff]

First of all I've only been diving for a short time (2yrs) and only have an Open water and Nitrox Certification. So I don't know much (anything) about Trimix. With that said....I personnely havn't had a problem with Narcosis with the diving I've done so far. Keep in mind I've stayed above 90 feet so far. I know that personnely I would consider not only taking this course but also paying the $20 for a fill if it would give me the added safety of reduced narcosis on a dive to 100-130 feet. I guess I feel that if Trimix makes the dive safer then the cost is a no brainer. That said I still think I'm going the traditional route of Advanced Nitrox/Deco first... I guess I feel more option/training posibilities can't hurt.

I'd be an interesting test to have some divers who are at the same skill level do dives with both Nitrox and Trimix to the 100-120 feet range and score them on how quickly and calmly they react to certain situations. That would be in my mind the best way to decide if this trimix course is a benifit....