Decompression Course

[doctormike]

In my mind, the biggest hurdle to completing the technical diving courses is not the academic work but the physical skills required. When I took my Intro to Tech course, I was already an instructor. My first day with double tanks, learning the required buoyancy and trim, etc. was one of the most humiliating days of my life. I realized then how very much I had to learn.

About a week ago I worked with a student on Intro to Tech. He said much the same thing. He is planning to wait several weeks before our next session together so that he can get into a pool several times to work on his skills.

This is another good point.

I do not think that it's a good idea to start a tech course by switching to backplate and doubles. We had one guy in our course who did that and he left the first day. I used my doubles for two years as a recreational diver before starting tech training, by that time I was more comfortable with doubles than with single tank. Even if you never go to tech, I find the doubles configuration very stable and having the redundancy is a real plus as well. Maybe not as nimble as a single tank for acrobatics, etc... but a very solid platform.

 

[Jim Lapenta]

Same here. Dived doubles for a year. Took intro to tech and helitrox with deco through naui. Then got a few hundred dives in with doubles and multiple stages.

 

[mulla]

Another vote for IANTD Advanced Recreational Trimix. You get exposure to Trimix, 48m depth rating, use of both 50% or 100% deco gas. I don't believe any other agency offer anything similar in a single entry level deco course. I did mine in sidemount.

 

[charlier]

I fully agree with Mike and Jim about getting lots of experience diving with twins before taking a tech class. I had not used twins in over a decade and for the past 200 dives in a tropical setting, I used a simple back inflate BCD (please, no comment). My first week on twins were not pretty. It took some time to develop good trim/buoyance and develop new muscle memory for BP/W and twins. I would not start tech course until you feel really stable and comfortable with twins.

 

[Ste Wart]

PADI Tec 40?

Non-deco course. You wouldn't get any extra time at depth

You could do GUE Rec 3. I don't know to which extend they'll accept your credentials though.

Fundies Rec Pass required, then find a GUE instructor that teaches req 3 in Australia. Not short-term practical.

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40m reef dive?

Single tank EANX 28%, multi-level profile. Job done.


Tech dives cost more for one dive than single tank diving costs for 2 in most resorts around the world. Enjoy single tank diving in Polynesia, don't worry about tech diving.

 

[Nasser]

40m reef dive?

Single tank EANX 28%, multi-level profile. Job done.


Tech dives cost more for one dive than single tank diving costs for 2 in most resorts around the world. Enjoy single tank diving in Polynesia, don't worry about tech diving.

This is pretty much exactly how I dove the last couple of liveaboards where sites where in this depth range. Multilevel staring out with about 10-15 minutes in the 40m range and moving up... average depth was about 17-20m and the Nitrox makes a difference in extending bottom time at that range (and less deco than air if you rack up a few extra minutes). Its a very good option if you don't want to go the tech route. Gas management and a good buddy (redundancy) is still quite important.

 

[doctormike]

Another vote for IANTD Advanced Recreational Trimix. You get exposure to Trimix, 48m depth rating, use of both 50% or 100% deco gas. I don't believe any other agency offer anything similar in a single entry level deco course. I did mine in sidemount.

Well, while trimix certainly has it's uses, I think that the OP wants to do tech for the same reason that I wanted to do it. We have a lot of great wrecks in my area (NYC) in the 100-140 foot range. So while I have been doing these without deco, it gets old fast getting up extremely early (or staying over on the boat), driving an hour to the dock, and spending the day at sea for two 18 minute dives. I wanted to be able to spend more time at these depths, and I don't think that trimix is worth the expense in that range.

I have never really felt the effects of narcosis down to the 140 feet. I realize that different people have different susceptibility to this, but my instructor feels that nitrogen narcosis effects at these depths is probably overrated and CO2 retention effects are underappreciated. While I'm not denying the role of trimix, it seems that it wouldn't be necessary for me (or for the OP).

 

[Ste Wart]

What is the price/availability of trimix in French Polynesia anyway?

Sent from my couch using tapatalk

 

[Jim Lapenta]

Another great point. trimix is expensive. The TDI Adv Nitrox/Deco course certs you to 150 feet and use of two deco gasses is covered. I like helium below 130 or so but it's not always practical from a cost and availability standpoint. For something like the Boland at 140 feet to the mud I'm ok on air or 26% for back gas with 50 and 100 for deco. I can get 30 minutes on the bottom and out of the water in a reasonable amount of time. And the cost is minimal.

To do that dive on Helitrox of say a 26-17 mix, which is not bad and what I first did it on in my helitrox class, is going to run 50-75 bucks just for back gas depending on where I get the fill. On top of 110 for the boat, 60 in fuel to get to the boat, and food. For the minimal benefit I get from it on a dive like that it's not worth it. Now for the St James at 165 it gets a bit more attractive.

There are also other dives like the Dean Richmond where on a penetration most of that would be around 110. No need for mix but I want 25 -30 minutes. So having a rich deco gas along with say 28% in the back gas is a nice option to have. So yeah adv nitrox and deco compliment each other nicely and should be taught together.

 

[mulla]

Well, while trimix certainly has it's uses, I think that the OP wants to do tech for the same reason that I wanted to do it. We have a lot of great wrecks in my area (NYC) in the 100-140 foot range. So while I have been doing these without deco, it gets old fast getting up extremely early (or staying over on the boat), driving an hour to the dock, and spending the day at sea for two 18 minute dives. I wanted to be able to spend more time at these depths, and I don't think that trimix is worth the expense in that range.

I have never really felt the effects of narcosis down to the 140 feet. I realize that different people have different susceptibility to this, but my instructor feels that nitrogen narcosis effects at these depths is probably overrated and CO2 retention effects are underappreciated. While I'm not denying the role of trimix, it seems that it wouldn't be necessary for me (or for the OP).

Very valid point. But simply doing ART doesn't mean you have to use Trimix for every dive down to your cert level. The way I see it, it doesn't hurt to gain knowledge in Trimix and its uses. If narcosis is not a problem then don't use it, but the theory that you've learned will contribute to your future courses should you wish pursue greater depths. More bang for buck IMHO.