Starting out in Tech Diving

[tbone1004]

@boulderjohn that's why I said "basically" intro to tech. I didn't think you could actually use staged decompression gases in Tec40, so while they may teach the theory, I would argue there is no point in teaching it if they can't apply it. I'd also argue that 10mins of deco on EAN50 is pretty useless if they let you do that.

If PADI says that you can't combine 40/45 into one course, or skip 40 entirely and roll the theory into 45, then that in my opinion is a bit ridiculous, but I don't like to play by their very rigid babystep rules.

I think a combo 40/45 course if you have experience is great *basically skip intro to tec*, or separate them entirely like every other agency does with intro then an/dp, but allow the instructor to make the call of whether they can skip tec40 or not.

The fact that they let you use Tec50 or Tec65 to get to advanced trimix is great. Tec50 could be useful for cave diving where we spend oodles of time at 100ft ish and having a bottom stage is nice, but I really don't see a point to it in open water.

They have some nuggets of brilliance in there, and some others that bring your brain to a screeching halt asking "quoi?

 

[Marie13]

Perdix works just fine with MacDive.

 

[luscioman]

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!

As others have said you will be going the Shearwater route. Also you state that you have plenty of air. Are you doing these dives on Nitrox or 21%?

 

[boulderjohn]

@boulderjohn that's why I said "basically" intro to tech. I didn't think you could actually use staged decompression gases in Tec40, so while they may teach the theory, I would argue there is no point in teaching it if they can't apply it. I'd also argue that 10mins of deco on EAN50 is pretty useless if they let you do that.

I have no idea what you mean by not being able to apply. They can do up to 10 minutes of deco. Please explain why that is not applying decompression theory.

Tec50 could be useful for cave diving where we spend oodles of time at 100ft ish and having a bottom stage is nice, but I really don't see a point to it in open water.

I have no idea what you are talking about with bottom stages. The focus of Tec 50 is using two deco gaxses. Apparently you think there is no point in using two deco gases on an open water dive. I know a lot of people who disagree with you. I just did a quick comparison of a 25 minute Tec 50 level dive to a wreck like the Hydro Atlantic, and the diver with 2 deco gases does 11 minutes less deco than the diver with 1 deco gas. If you rpefer hanging out in the water for that extra time, I guess you are right.

 

[boulderjohn]

If PADI says that you can't combine 40/45 into one course, or skip 40 entirely and roll the theory into 45, then that in my opinion is a bit ridiculous, but I don't like to play by their very rigid babystep rules.

I think a combo 40/45 course if you have experience is great *basically skip intro to tec*, or separate them entirely like every other agency does with intro then an/dp, but allow the instructor to make the call of whether they can skip tec40 or not.

The PADI coruses can be combined all you want, but they have to be taught in sequence. That is the big difference between the TDI program and the PADI program--they are designed completely differently. TDI teaches Advanced Nitrox in one course, and it teaches decompression procedures in another. The only way you can teach them in a meaningful way is to combine the two course and and have the instructor rearrange the lessons and skills in an order that makes sense sequentially. The PADI program combines the learning of the concepts in the course sequence, so it is already structured in a way that makes sense sequentially.
[/QUOTE]

 

[decompression]

As mentioned in the merged thread, tech training is where you can select an instructor vs an agency. Unless there are particular reasons for a specific agency. Identify your goals both imeadiate and long term, then find the course that fits these goals. And if you have the luxury of selecting the instructor to teach these courses then consider a few points;
How experienced is the instructor?
How often are they tech diving and tech instructing?
Are they trained above the level they are teaching?
Who were they trained by?

Just a few of many questions you can ask. I really appreciate instructors that utilize the philosophy of "payment for this course does not guarantee a certification....."

 

[tbone1004]

@boulderjohn it didn't state that on the website and hadn't dug into the standards. If they allow 10mins of backgas that's great. They say conduct limited decompression so not sure what that means , but I think 10min on accelerated deco on ean50 is a waste of teaching time and better spent in an an/dp course. 10 mins of backgas deco is not much teaching time so may as well do that.
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. My comment was based on what their website says about the course. As there is no mention of carrying an extra bottle until the Tec45 course, then they need to update their website to actually reflect what the course does since it is apparently very inaccurate.

on the subject of dual deco gases. for a 25 minute bottom time to 165' on 18/45, I'm not adding the complexity and hassle of a second bottle.
My math says O2 only, 74 min total
50% only 63 mins
both 57 mins.
If you do it on 21/35
02-64
50%-58
both-53
Again, no benefit to carrying two deco mixes. Carry a single bottle of 50% and call it a day. To get the 11 min benefit you must be comparing O2 only to both ean50 and O2, which is backwards from what I think most people recommend for that kind of dive.

Give me EAN50, and no way I'm going to bother taking oxygen either as the only gas or in addition to the EAN50 for a 6 minute benefit with both or an 11min deficit as the only gas.

When they combine in sequence, is there any overlap that can be used to shorten the courses like is done with everyone else or do you have to go through the entire course? I.e. it seems like Padi Tec Deep is 40+45+50 which makes sense to me. If each of these courses are say 2 days, with the overlap inherent in both, you should be able to consolidate into 5 with a lot of the dives covering portions of both of the courses. Is that a thing they allow or do you just go through the whole course, get the card, then start the next course the next day?

 

[stuartv]

TDI teaches Advanced Nitrox in one course, and it teaches decompression procedures in another.

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.

 

[Frackingawesome]

I would take a PADI trimix course with Martin Robson long before I would with a new TDI trimix instructor just as I would take a TDI trimix course with John Chatterton long before I would with most PADI trimix instructors.

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...

 

[tbone1004]

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.

advanced nitrox is not irregularly taught as a separate course for some scientific diving applications. Being able to dive all day on say EAN50 at 50-70ft instead of EAN36 is nice since there are restrictions on not going into decompression for a lot of those dives.

You get 100 mins on the first dive with GF50/80 on EAN50 vs 70 mins on EAN36 or 50 mins on EAN32. Not sure what on the NOAA tables since I don't have them in front of me but it's pretty significant for that kind of diving