Starting out in Tech Diving

[stuartv]

What computer should i get.

A Shearwater Petrel, Petrel 2, Perdix, or Perdix AI. They are basically the same with the following exceptions:

Petrel does not have a compass. The compass was added starting with the Petrel 2.

The Perdix and Perdix AI are the same size as each other and they are a fair bit smaller than the Petrel/Petrel 2.

The Perdix AI has air integration. I.e. you can put a transmitter on your tank so your Perdix AI will display your tank pressure (and record your tank pressure in your dive log).

In your tech training, you are almost certainly going to be trained to plan tech dives using the Buhlmann ZHL-16C with Gradient Factors algorithm. Thus, you want a tech computer that runs that algorithm. Other tech computer wannabes may offer trimix support and multi-gas support, but they don't support Buhlmann w/GF, so you wouldn't be able to use them in your training except to run them in gauge mode. E.g. The Galileo 2 (or original Galileo) and the Suunto Eon Steel.

 

[tbone1004]

In your opinion, Would it make sense to travel to Florida and pay the extra to do John Chatterton's Advanced Wreck and Deco Class? i think the cost is $1800 for a full week of training. Plus room and board... I want to do this and i want to do it right... but i also dont want to buy the brightest shinnyist thing just cause it is bright and shinny...

If you want to do wreck diving, it's actually not that expensive.
Tech courses are typically $200/day for the instructor, so on a 5 day course that's $1000 of it
Materials and cards are probably $100 or $150 for TDI? unsure, but call it $100
You also get 10 boat dives, so $70/dive plus your gas fees.
You'll probably have a $200 gas bill, plus tipping of about $100.
You can do it inshore for less money because you don't have boat fees, but you don't have as interesting of an experience in the environment that you are wanting to dive in.

There are several instructors up in the mid-atlantic that may also be worth looking into. I'd try reaching out to Joe Cocozza and talking to him since he's an active wreck diver up there

 

[stuartv]

In your opinion, Would it make sense to travel to Florida and pay the extra to do John Chatterton's Advanced Wreck and Deco Class? i think the cost is $1800 for a full week of training. Plus room and board... I want to do this and i want to do it right... but i also dont want to buy the brightest shinnyist thing just cause it is bright and shinny...

TDI AN/DP is the first step (on the TDI path) in tech training. I have been told that it is the hardest because it is the biggest amount of "stuff" to learn in one class. You're going from single tank diving with only one gas, no decompression, (probably) extremely informal (or almost no) dive planning and no big requirements for maintaining good trim and buoyancy to diving doubles, carrying a deco cylinder, serious dive planning, and new dive skills that have to not only be learned to a level of basic proficiency but that also require significantly better buoyancy and trim than what you've had to have before.

Do you really want to learn a whole pile of new skills plus be required to make improvements to the skills you already have and then be pushed out into the world to "sink or swim" after only 6 days in a row of training?

My AN/DP course was spread out over a number of months worth of weekends. We did a bunch of pool dives, then a whole bunch of quarry dives, all the while returning to the classroom for dive planning sessions, then finally out for open ocean checkout dives. I think I came out a much better, safer diver for having had all that time to learn and practice and be corrected and digest and try again to do it better next time, versus getting it all dumped on me over 6 days then being sent off and hope I can remember it all and do it "for real" when I'm on my own with nothing but a buddy who also has 6 days of experience.

That said, when you look at the fact that JC's classes include the boat rides you need, I think his prices are somewhat of a bargain compared to what other places charge.

 

[stuartv]

Simple question. Is there a consensus on PADI v. STI for there tech courses? Or is there another organization that i should look at?

I like the TDI progression. I have TDI Helitrox and am working on TDI Trimix, so I am not as knowledgeable about the overall subject as others here. But, MY take is that there is a progression from being an OW diver to diving hypoxic trimix with certification to 100m(330'). If you break up into too few steps, the steps are too big and that's not safe. But, if you break it up into too many steps, then it takes longer with no real benefit to the student and the negative of spending more money than necessary.

I feel like TDI hits just the right balance.

You can take Adv Nitrox, Deco Procedures, and Helitrox all as one course, as your first step. You do not have to take Intro to Tech first.

With AN/DP/H, you are certified to dive to 45m(150'), do unlimited deco, with at least one deco gas, use up to 100% oxygen for deco, and use up to 20% helium in your mix. The instructor has the flexibility to teach use of more than one deco gas during this course but my instructor did not and I suspect that most are the same.

The next step is Trimix. With that, you are certified to dive to 60m(200'), use at least 2 deco gases, and use as much helium as you want.

The final step is Adv Trimix. With that, you are certified to dive to 100m(330'), use more than 2 deco/travel gases, and use gas mixes with less than 18% oxygen (aka hypoxic mixes).

You take 3 classes and you are good for pretty much any depth.

Other agencies that break it down into more steps seem like they are making it unnecessarily long, drawn out, and expensive. For example, I personally don't see any reason that I would want to pay for a class to certify me for only 40m(130') of depth, 10 minutes of deco, and use of up to 50% oxygen. I think that is a really small step that is just extra time and money for no reason. Having the first step be for certification to 45m, unlimited deco (which is, in reality, limited by only carrying 1 deco cylinder), and up to 100% oxygen makes a lot more sense to me.

 

[dberry]

I think the $1800 is for JC's triple combo - AN/DP + adv. wreck (TDI). I'm not sure if he offers just the AN/DP combo, but it should be less. It's a very intense 5 day experience, with long hours in the classroom after morning dives. I enjoyed it, but I tend to agree with @stuartv: it would have been better (for me) to have spread it out over a longer period of time. YMMV.

But on the plus side, there's a lot to be said for dealing with all the new variables and task loading while in relatively warm water with good viz (i.e. Pompano Beach, FL) versus the cold, dark NE Atlantic wearing a drysuit.

 

[stuartv]

I think the $1800 is for JC's triple combo - AN/DP + adv. wreck (TDI). I'm not sure if he offers just the AN/DP combo, but it should be less. It's a very intense 5 day experience, with long hours in the classroom after morning dives. I enjoyed it, but I tend to agree with @stuartv: it would have been better (for me) to have spread it out over a longer period of time. YMMV.

But on the plus side, there's a lot to be said for dealing with all the new variables and task loading while in relatively warm water with good viz (i.e. Pompano Beach, FL) versus the cold, dark NE Atlantic wearing a drysuit.

JC does offer just AN/DP. $1200. 6 boat dives over 3 days. $1200 for AN/DP including all required boat rides seems like kind of a bargain, to me. But, as you say, I am glad to have had longer to train before I was sent out to do it without an instructor watching me. When I personally started AN/DP, I was not remotely ready with my dive skills be ready to go out and do deco dives on my own 3 days later. I finished AN/DP well over a year ago and have done a number of deco dives since and I am STILL really learning how to do it....

Deco Diver | Shadow Diver | John Chatterton

The cold, dark Atlantic is why we learned all the skills in the pool first. Then practiced them a lot during simulated deco dives and ascents with gas switches (still just using air) in the quarry before finally going out for checkout dives in the ocean.

 

[KenGordon]

I have been diving a few years now and am really enjoying diving the wrecks off the New Jersey Shore. Up to this point i have been diving single hp steel 100. This makes loading un unloading the boat REALLY nice but i am starting to find i want more bottom time and the ability to go deeper. Even a steel 100 at 100-130 feet i have plenty of air left when i hit my NDL.

So my question. What computer should i get. I was looking at the ScubaPro G2 that just came out but that does not work with MacDive software. Currently i use a Sunnto Viper Air that i MIGHT keep for use as backup in gage mode.

I really dont want to start a which is better chevy or ford conversation but some computers with the reason while you like them would be Very Very Helpful.

I do plan on working my way to advanced Trimix... or what ever PADIs equivalent is... So a computer that will grow with me would be awesome!

You can use the Vyper Air for Nitrox deco diving. It can handle a bottom gas and a deco gas. That is enough for the likes of AN/DP. Today you can download DM5 from Suunto and plan some dives you might want to be doing so you can see how your bladder will cope. With the money you save you can do a week's diving.

Spending money on kit before a course is a great way to buyer's remorse. Do the course and learn what matters, then buy the kit when better informed. You may be able to try out the recommendations above and find out at no cost if they are good.

If you are serious about 60 to 100m stuff then there will be a rebreather in your future.

 

[uncfnp]

...other than possibly by some special and very unusual student

:blush:

 

[boulderjohn]

Do you know a single TDI instructor that teaches those two courses separately (other than possibly by some special and very unusual student request)? TDI doesn't teach anything. TDI instructors pretty much all teach Adv Nitrox and Deco Procedures as one course, I believe.

As tired as I am of repeating this, I will give it another shot.

1. For TDI Advanced Nitrox and Decompression Procedures are two different courses with two different books and two different certification cards.
2. A diver can be certified for Advanced Nitrox without taking the Decompression Procedures class, and there may be times a diver will want to do that. One example would be getting a card to get oxygen for recreational rebreather. Those occasions will be rare.
3. As the courses are designed, the standards are separate. The list of skills a students must demonstrate on a dive in the Advanced Nitrox course do not include decompression, because decompression theory is wholly contained in another course.
4. For probably 95% of all divers (and maybe more), this makes no sense. Consequently, TDI allows the courses to be taught simultaneously, and even adjust the standards accordingly. When it is done that way, fewer divers are required. If the sequence includes Intro to Tech, all three can be combined, and even fewer dives are required. When the courses are combined, the instructor can move requirements from one course to another in a way that makes sense.
5. I always taught AN/DP as one combined course myself.

Is there anything wrong with what I wrote above? Have I said anything different anywhere else? Have I ever said there is anything wrong with this?

 

[boulderjohn]

A buddy just explained that EAN50 can be used to add conservatism to deco but not accelerate it, so that makes me scratch my head a bit, but whatever.

I have no idea what this means myself.

You need to get your information from more reliable sources. A tec 50 graduate can do any amount of decompression using any mix of decompression gases with a maximum of 2 deco gases. There are no limitations.