SSI/TDI v PADI Tec Training

[mockney]

Hi All,

I am newly qualified MSD (with PADI). So I am thinking about my next steps in terms of scuba training.

I have decided not to bother with Divemaster, I am not really into teaching and for me dives are just a fun way to relax at the weekend, so Divemaster route doesn't seem to fit.

There are a number of wrecks around Sydney that are just out of reach of the recreation dive limits and I need to take Tec training in order to dive them so this seems to be my next logical step for development of my dive skills.

Now the question... I see both SSI/TDI and PADI both have Tec courses, PAID's seems to be more progressive i.e. a further course for every 5 meters deeper whereas TDI seem to have a Advanced Nitrox + Deco course available that doesn't limit by depth (I could be wrong here).

My local LDS offer both PADI and TDI courses, they advise to move over to TDI as the course also trains you on the use of double's which is something I want to use whereas again I understand the PADI Tec 40 course is focused training on single tank only. Personally I would prefer to stay with PADI but not if there is a clear advantage to taking my Tec training with TDI. I would be keen to hear any thoughts and views on this subject to help me make an informed decision.

Many Thanks

 

[WarrenZ]

I personally enjoyed my switch to TDI I did the AN/DP class which gives you access to any mix of O2 that you deem reasonable for the dive however the certification is limited to 150' so the same limit as Tec 45. The TDI training seemed to be more about the content and knowledge of the course then the selling of another specialty I had experienced in other agencies courses. If you ware interested in reading about my experience my write up is in the December 2015 issue 21 of Tech Diving Mag.

My personal limit on air is 150' as at that depth I am feeling enough narcosis I dont want to push beyond that depth. Therefor I will be looking at taking a trimix course before pushing deeper.

 

[KenGordon]

For tdi you might be expected to do intro to tec first. This is entry level non deco twinset (doubles), trim, buoyancy and planning. An/DP is proper hard work and not the place to learn how to do shutdowns etc, it is the place to learn stage handling, gas switching, team stuff, etc.

Intro to tec is very worth while, although the certification does not 'let' you do anything new it will actually teach you a lot.

I suggest doing that, spending some time doing easy dives with a twinset and then doing an/DP (the helitrox version) once you are comfortable.

The progression through PADI may be similar if you get the right instructor, but since they label the qualifications by depth it might not be so obvious what each one entails.

 

[DevonDiver]

My background - I initially qualified for technical diving with TDI but as a tech instructor with PADI TecRec (was DSAT) in 2007. I've subsequently trained/taught for several other agencies.

PAID's seems to be more progressive i.e. a further course for every 5 meters deeper whereas TDI seem to have a Advanced Nitrox + Deco course available that doesn't limit by depth (I could be wrong here).

TDI Advanced Nitrox doesn't qualify a depth. It merely qualifies to use >100% O2. As such it's pretty meaningless by itself. Deco procedures qualifies to 45m. The Adv Nitrox and Deco Procedures only make sense when taken together.

PADI Tec40 qualifies for non-accelerated 10 min max deco (using >50% o2 for conservatism only) up to 40m depth . It's meant as a transitional course between rec and tec. Tec45 upgrades to full unlimited and accelerated, decompression using one deco gas only (>100% o2). Tec50 brings in a 2nd deco gas (4+ tanks total).

AN + DP = Tec45
Extended Range = Tec50

Importantly; the main emphasis of PADI tech courses isn't the incremental depth increase. This is largely irrelevant. What matters is the introduction of more complex or hazardous procedures.

Tec40 is kept very safe. Very light deco plus an ascent gas to clean out your nitrogen. No critical issues with lost deco gas and/or bottom gas. The dives are relatively forgiving of mistakes. It is also beneficial for advanced recreational divers who might complete otherwise aggressive no-deco dives... and can introduce technical diving approaches to help mitigate risks.

Tec45 is full technical diving. Depth is "only"|45m.... but you can incur significant decompression if your bottom time is long. You have the decompression tools (50-100% o2) and skill to complete this safely. Most dives in this range can be done with bottom gas for deco (if deco gas were lost). There is only one deco gas which reduces the risk of oxygen toxicity issues through diver error.

Tec50 introduces a second deco gas. This demands zero mistakes in your gas switching and cylinder/regulator handling. As such it is far more significant than the meagre 5m depth increase in qualification. The extra depth means much longer deco (relevant to bottom time) - so a 2nd deco gas allows 2 stages of accelerated deco... cutting deco times. However this length of deco can rarely be completed using back-gas. All factors and failures become much more critical. Dives are conducted with >4 cylinders,.so this starts preparing your for trimix diving later.

When I teach tech, I urge student divers to think of dives in respect to the TTS (time to surface) and not the depth. What matters is how long (minutes) the surface is from you... not how far (meters).

My local LDS offer both PADI and TDI courses, they advise to move over to TDI as the course also trains you on the use of double's which is something I want to use whereas again I understand the PADI Tec 40 course is focused training on single tank only.

PADI Tec40 is usually taught in doubles (or sidemount). It is very rare for it to be taught with a single tank..It should not be taught in single tank (plus pony) for divers who intend to complete further technical diving courses. Most entry-level tech courses offer a single tank (plus pony) option. This is only meant for divers who don't intend to progress further into tech diving... i.e. divers who want some tech procedures and knowledge to improve their recreational diving.

There is no reason why your local dive center couldn't teach Tec40 in doubles. If they are saying they can't then they have another motive for doing so. It's neither normal practice nor an agency standard. Single tank (plus pony) is only intended for people who won't progress beyond Tec40 - further courses (Tec45+) need doubles.... and Tec40 is meant to prepare for this.

Of further note: PADI TecRec also now offers a (2-dive) extension to the Tec45 and Tec50 courses which qualifies normoxic trimix to those depths. A wise addition if personal narcosis management discourages deeper air diving.

Hope that helps.

 

[tstormdiver]

As has been mentioned many times here.... More important than the agency, is the instructor. Look for one who is very competent & thorough in the course & you really can not go wrong.

 

[boulderjohn]

Like Andy, I have taught both the TDI course and the PADI course. I agree with his assessment and would like to add a little more to it.

The normal progression for TDI is Intro to Tech/Advanced Nitrox/and Decompression Procedures. The program is very much back loaded, meaning you don't get to the meat of the course until the end of that progression. Intro to Tech is very much what it says it is--just an introduction, and Advanced Nitrox does not teach you anything about decompression, either. You don't get any of that until you get to Decompression Procedures, the last course in the sequence. That's where most of the information lies. Because of that, TDI allows you to teach AN/DP as one course, and they also allow you to teach all three as one course, in which case the requirements are different--you can combine skills from the three courses in the dives and finish with fewer required dives. When you are done with the three courses, you are at about the same level of certification as PADI Tec 45.

In contrast, PADI front loads the course sequence. Although Tec 40 only gets you limited decompression, you have to learn a heck of a lot of deco theory to get it. It is also SOME decompression--with TDI, you aren't certified for ANY until the end of the course sequence. (Like Andy, I can't believe anyone would teach Tec 40 in anything but doubles.) Tec 45 adds a lot more theory. I have certainly not counted words, but it would not surprise me to learn that PADI Tec 40/45 has twice as much volume of content as TDI AN/DP. By the time you get to Tec 50, you pretty much have all the theory done, so that course focuses on the process of adding a second deco gas. The academic content of the course is required for the PADI Trimix course, so if you were to cross over for the PADI trimix using a qualifying certification for that course, you would still need to complete at least the knowledge reviews for tec 50.

 

[WarrenZ]

Thanks for clearing that up I did the combined AN/DP progression so they seem like one course to me. I also skipped the Intro to Tech so I have no input on that one.

 

[boulderjohn]

Thanks for clearing that up I did the combined AN/DP progression so they seem like one course to me.

As I understand it, the only reason you would ever want to take Advanced Nitrox as a stand alone course is so you can get O2 fills for a recreational rebreather. If you intend to take DP when done with AN, it would be downright silly to take them as two separate courses. The AN by itself gives you no value, since you can't do decompression, and since you can't do decompression on the required dives, those dives have little value. Then you would take the DP course and have all sorts of challenging dive requirements piled on. It is much, much better to be able to combine them.

 

[rongoodman]

The nice thing about TDI is that you can combine Helitrox with AN/DP so you're doing your deeper training dives with a clearer head.

 

[DevonDiver]

The nice thing about TDI is that you can combine Helitrox with AN/DP so you're doing your deeper training dives with a clearer head.

As mentioned - PADI now offer an extension to either Tec45 or Tec50 that qualifies the student for normoxic trimix within the given depth range. It's two further dives (total 6 per module, rather than 4).

There's also the option of Tec65 - which is normoxic trimix. That requires Tec50 as a prerequisite though. The new extensions enable trimix to be brought into play at a much earlier stage. A wise move... that brings PADI into line with most other tech agencies.