TDI training

[texdiveguy]

It is my hopes that within the next 5 years to be able to enter into basic 'wreck diving' a bit beyond the norms of sport diving (were talking depths of 150' with very limeted penetration). I am in the process of setting my training goals and had a question or two. As we all know experience is many times the very best teacher,,,,and that I am gaining on each outing. Now to the acdm. of advanced training....I have several TDI training fac. in my area. I am trying to get a feel for the best way to invest my monies and time in several TDI courses. The courses I am looking at are: Decompression Proc. and Extended Range atnd at some point a bit down the road Adv. Wreck. I want to get your feelings on the best order to take these--- I was thinking Deco Proc. and then Extn. Range...? Also is it a must to take Advanced Nitrox, or will the other 2 courses cover this to an excp. level? Thanks for any input.

 

[Hyper-limits]

It is my hopes that within the next 5 years to be able to enter into basic 'wreck diving' a bit beyond the norms of sport diving (were talking depths of 150' with very limeted penetration). I am in the process of setting my training goals and had a question or two. As we all know experience is many times the very best teacher,,,,and that I am gaining on each outing. Now to the acdm. of advanced training....I have several TDI training fac. in my area. I am trying to get a feel for the best way to invest my monies and time in several TDI courses. The courses I am looking at are: Decompression Proc. and Extended Range atnd at some point a bit down the road Adv. Wreck. I want to get your feelings on the best order to take these--- I was thinking Deco Proc. and then Extn. Range...? Also is it a must to take Advanced Nitrox, or will the other 2 courses cover this to an excp. level? Thanks for any input.

If you want to dive to 150ft you will have to take the Advanced Nitrox or you will be decompressing forever if you are using your back gas. Also diving on air to 150' on a wreck with even limited penetration is not a very clever thing to do anymore, that why Trimix is the way to go when diving under 130ft. But to answer your question you could take the Deco Procedure without the Advanced Nitrox. Most instructor with teach both course at once. If you take the advanced nitrox (40% right up 100%)you can use a higher % of nitrox or even pure O2 to speed up deco.
Not sure a 100% but I'm pretty sure you need Advanced Nitrox to take the Ext. Range.

 

[texdiveguy]

If you want to dive to 150ft you will have to take the Advanced Nitrox or you will be decompressing forever if you are using your back gas. Also diving on air to 150' on a wreck with even limited penetration is not a very clever thing to do anymore, that why Trimix is the way to go when diving under 130ft. But to answer your question you could take the Deco Procedure without the Advanced Nitrox. Most instructor with teach both course at once. If you take the advanced nitrox (40% right up 100%)you can use a higher % of nitrox or even pure O2 to speed up deco.
Not sure a 100% but I'm pretty sure you need Advanced Nitrox to take the Ext. Range.

Yep Trimix is in the future for sure,,,thanks for bringing that point up. Have you taken these courses,,,,with Deco Proc., is that just classroom...or are there also actual dives involved??

 

[matt_unique]

It is my hopes that within the next 5 years to be able to enter into basic 'wreck diving' a bit beyond the norms of sport diving (were talking depths of 150' with very limeted penetration). I am in the process of setting my training goals and had a question or two. As we all know experience is many times the very best teacher,,,,and that I am gaining on each outing. Now to the acdm. of advanced training....I have several TDI training fac. in my area. I am trying to get a feel for the best way to invest my monies and time in several TDI courses. The courses I am looking at are: Decompression Proc. and Extended Range atnd at some point a bit down the road Adv. Wreck. I want to get your feelings on the best order to take these--- I was thinking Deco Proc. and then Extn. Range...? Also is it a must to take Advanced Nitrox, or will the other 2 courses cover this to an excp. level? Thanks for any input.

You would need Adv. Nitrox and Deco Procedures for Extended Range. Deco Procedures certifies you to dive to to 150' with staged decompression. I personally would not bother with Extended Range. Narcosis to those depths on air would be significant. I found the most 'noticeable' change when I descend below 140' on air/leaned nitrox. In reality you are affected much more than you often feel.

Do you have a basic Nitrox cert? Even a 40% deco mix would greatly reduce your required deco time. Higher %'s available after Adv. Nitrox would reduce deco time even more.

Last summer I was doing a wreck at 160' with leaned Nitrox for back gas and 40% EAN for deco gas. My buddy was on trimix and 80% 02. His enriched air depth in the sand was 76' as I recall, mine was 146'! At our last deco stop (20') he was able to surface when I still had 19 minutes remaining! I was sold on Advanced Nitrox and Trimix from that point forward.....I had completed Deco Procedures the year before (great class). I found the Deco Procedures class to the be the best I have ever taken.

--Matt

 

[texdiveguy]

You would need Adv. Nitrox and Deco Procedures for Extended Range. Deco Procedures certifies you to dive to to 150' with staged decompression. I personally would not bother with Extended Range. Narcosis to those depths on air would be significant. I found the most 'noticeable' change when I descend below 140' on air/leaned nitrox. In reality you are affected much more than you often feel.

Do you have a basic Nitrox cert? Even a 40% deco mix would greatly reduce your required deco time. Higher %'s available after Adv. Nitrox would reduce deco time even more.

Last summer I was doing a wreck at 160' with leaned Nitrox for back gas and 40% EAN for deco gas. My buddy was on trimix and 80% 02. His enriched air depth in the sand was 76' as I recall, mine was 146'! At our last deco stop (20') he was able to surface when I still had 19 minutes remaining! I was sold on Advanced Nitrox and Trimix from that point forward.....I had completed Deco Procedures the year before (great class). I found the Deco Procedures class to the be the best I have ever taken.

--Matt

Hey Matt.... thanks for the reply and info.. I do have basic EAN certf.. It sounds from what you are saying that Adv. Nitrox is a plus and so is Deco Proc. to at least get my self on track.

 

[DA Aquamaster]

I'd agree with the recommendation to do both Advanced Nitrox and Deco Procedures. This will get you certified to 150 ft. and the accellerated deco procedures you can then use will cut the deco time on a moderate deco dive of 150 ft for 20 minutes almost in half.

I agree narcosis is a concern and I would personally not bother with Extended Range as 150' on air is already extended enough without pushing it another 20 ft deeper. Extended range is also no longer a pre-requisite for trimix so I see it as a largely useless course.

That said, I am not a trimix zealot by any means and feel that air or cooler nitrox mixes around 25% can be appropriate gasses for 150 ft dives provided you have the experience and ability do to it safely.

 

[texdiveguy]

I'd agree with the recommendation to do both Advanced Nitrox and Deco Procedures. This will get you certified to 150 ft. and the accellerated deco procedures you can then use will cut the deco time on a moderate deco dive of 150 ft for 20 minutes almost in half.

I agree narcosis is a concern and I would personally not bother with Extended Range as 150' on air is already extended enough without pushing it another 20 ft deeper. Extended range is also no longer a pre-requisite for trimix so I see it as a largely useless course.

That said, I am not a trimix zealot by any means and feel that air or cooler nitrox mixes around 25% can be appropriate gasses for 150 ft dives provided you have the experience and ability do to it safely.

DA... thanks for the comments,,,,the more I read and listen to the tec side I think Adv. Nitrox and Deco Proc. are the first steps I will take. Now i will start considering the basic hardware i will need at least to allow me to take the courses on my on gear,,,,,any comments would be great.

 

[DA Aquamaster]

AL 30's or AL40's make great deco bottles as they are small in diameter and are easier to carry in the water than an Al 80. Al30's or 40's are a good balance for your backgas and are well matched for the normal deco requirements in the 150 ft range.

Some divers advocate using AL 80's for deco bottles but they are overkill unless you are going very deep and are going to need to use one for travel gas and relatively long deep stops on something like Nitrox 36. But you would be well into trimix territory at that point. There is also some merit to using an 80 for deco gas on longer trips where you want several dives out of one tank. Given that an AL 30 or AL40 costs nearly as much as an AL80, it is cheaper to bring two AL 80's than four AL 40's but two 40's are a lot handier in the water than one 80. Plus you can carry two separate gases in the pair of 40's and optimize the deco more, so if you have the funds it makes sense to go that route. Steel deco tanks are generally avoided as their negative bouyancy traits can be problematic.

For backgas, a pair of AL 80's are an affordable way to start with doubles and offer reasonable bottom times for the depths you are considering. 20-25 minutes at 150 ft with a 1/3 reserve should be possible if your sac is reasonable. AL80's are not negatively bouyant when empty so they make a good choice if you will be diving with a wet suit. E7-100's would be an excellent choice as well as they are similar to AL80's in size and weight but hold another 23 cu ft of gas each. They are however very hard to find and hideously expensive as they are in short supply.

Whatever you get, go with DIN valves on the back gas and deco tanks.

For deco regs I like simple unbalanced piston designs Like the Scubapro Mk 2, Aqualung Calypso, etc. as they are small and light weight, mechanically simple and well suited to O2 use as no dynamic o-rings are exposed to high pressure gas. I use Scubapro Mk 3's with Balanced Adjustable second stages mostly because I own a lot of them and prefer them to my Mk 10's in that application. That is however a personal choice and opinions will vary widely.

Some divers advocate having second stage purge covers that can be removed underwater without tools. It probably makes sense in a cave, but I cannot envision doing this successfully in open water at a 70' stop in a current. A possible alternative is to leave the second stages attached to the LP hose finger tight (obvious potential downside to that) or carry a small crescent wrench in a pocket and swap second stages if one bites the dust. In a real pinch, you could also swap piston first stages between tanks underwater as they will usually handle the flooding ok, but will need serviced after the dive.

Primary regs should both be first rate, well maintained and very reliable. I prefer Scubapro Mk 16's or Mk 20/25's with a Balanced Adjustable, G250 or D400 second stage, but Apex regs are also great as are top end regs made by several other companies.

A backplate and a suitable wing is a must. Aluminum is a good choice for the backplate material if you travel or will be diving a wet suit. Harness styles vary from a basic web harness to a transplate style harness with shoulder pads, dual quick releases, etc. I pefer a middle of the road web harness with pivot rings and a quick release. It is in my opinion a nice blend of simplicity, durability and comfort.

Wing size will depend on the rest of your configuration, exposure protection, where you will be diving and to some extent who you will be diving with. Expect big discussions on this one.

 

[Hyper-limits]

DA... thanks for the comments,,,,the more I read and listen to the tec side I think Adv. Nitrox and Deco Proc. are the first steps I will take. Now i will start considering the basic hardware i will need at least to allow me to take the courses on my on gear,,,,,any comments would be great.

Some of the gear you will need for the advanced Nitrox and Deco procedure.
IMO Before you buy anything you should talk to your instructor.

Primary cylinders. I did the deco course with twin 72's
Lift bag/SMB, usually 50lbs of lift minimum.
Reel.
1 deco bottle. IMO 40cf is the perfect size
2 Computer/bottom timer.
3 regulators. Usually one reg with 7' hose
BP and wings. Not necessary depending of what kind of BC you have right now.
Exposure suit adequate for the open water environment.
Slate/wet notes.

Cheers

Al

 

[texdiveguy]

Both DA and Al again thanks for the first hand input,,,,this really helps,,,,,,I was thinking a Al40 and twin Al80's. I will probably have to go with a new BC.....using a Mares Vector 1000AT which is a great sport BC but has limited lift even for entry deco diving. Also the 02 clean tank/reg. will be a new investment. *I know others are benifiting from your replies as well as I am......comments like yours will go along way in making proper progress in this tec gear-up and classes. Now going to have to get to a few more sit-ups !