[yet another tech PADI vs TDI thread] question for instructors

[boulderjohn]

Here is a difference I actually did not know about until recently because I will admit I did not read the standards for TDI Decompression Procedures with a truly critical eye when I was teaching them. I always had my students in that class do decompression dives to complete the course, and I suspect pretty much all TDI instructors do that as well. It is not required by the standards, though. Nothing in the standards requires students to go into decompression before you certify them to do decompression dives. PADI divers are required to do decompression dives to be certified to do decompression dives.

 

[Dirty-Dog]

Here is a difference I actually did not know about until recently because I will admit I did not read the standards for TDI Decompression Procedures with a truly critical eye when I was teaching them. I always had my students in that class do decompression dives to complete the course, and I suspect pretty much all TDI instructors do that as well. It is not required by the standards, though. Nothing in the standards requires students to go into decompression before you certify them to do decompression dives. PADI divers are required to do decompression dives to be certified to do decompression dives.

Interesting.
IANTD requires simulated deco dives initially, to demonstrate planning and ability to hold stops and such, but you do have to do actual deco before you get certified. I'm kind of surprised to hear TDI does it this way.

 

[Trace Malinowski]

John, out of curiosity, what makes a dive a decompression dive according to PADI? Is it based on tables, computers, or as long as you take a table or computer into deco you've met the standard?

When I taught TDI Advanced Nitrox & Decompression Procedures, I'd take students into The Hole at Dutch Springs at 101 - 105 feet satisfying the depth requirements. Most students wanted to "go into deco" after we did our mock dives. I'd just use a schedule that would place them in deco according to tables, but my computer would either clear before the stops or never actually go into deco.

They'd be happy, but the schedule would be really forgiving. For example, if I just wanted to create a square dive profile, but run multi-level on the computers, I'd do something like this:

MultiDeco 4.14 by Ross Hemingway,
VPM code by Erik C. Baker.

Decompression model: VPM - B

DIVE PLAN
Surface interval = 1 day 0 hr 0 min.
Elevation = 0ft
Conservatism = + 2

Dec to 105ft (1) Air 60ft/min descent.
Level 105ft 28:15 (30) Air 0.88 ppO2, 105ft ead
Asc to 40ft (32) Air -24ft/min ascent.
Stop at 40ft 1:17 (34) Air 0.46 ppO2, 40ft ead
Stop at 30ft 4:00 (38) Air 0.40 ppO2, 30ft ead
Stop at 20ft 3:00 (41) Oxygen 1.60 ppO2, 0ft ead
Stop at 10ft 6:00 (47) Oxygen 1.30 ppO2, 0ft ead
Surface (47) Oxygen -20ft/min ascent.

Off gassing starts at 76.1ft

OTU's this dive: 39
CNS Total: 17.3%
Gas density: 5.0g/l

98.9 cu ft Air
7.5 cu ft Oxygen
106.4 cu ft TOTAL


DIVE PLAN COMPLETE

We might only be in The Hole for 5 minutes, then swim to shallower attractions, but on gauge mode the students would be in deco. If I ran my Nitek 3 (my computer at the time), it might never display a mandatory stop.

 

[boulderjohn]

hn, out of curiosity, what makes a dive a decompression dive according to PADI? Is it based on tables, computers, or as long as you take a table or computer into deco you've met the standard?

I think the definition of going into deco is the same for all agencies. If the algorithm you are using for dive planning says you owe a decompression stop, you are in deco.

 

[ChuckP]

A very premature question in my list of questions but - Where does one go to obtain the required number of dives to get to some of these teaching levels?

I spent a month in Cozumel finishing PADI divemaster, I'm going back for three months there interning for IST - there's a lot of people flowing thru there so it makes it easier to gain some experience.

I'm looking at tech training to be able to lead "light" deco dives in Cozumel, possibly even teach, as this is where I think I want to call home.

I have a local shop that is SSI - I'm not real clear on the politics behind the scenes but he's pushing TDI, but there really just isn't the availability, or better said, he isn't available to dive enough to gain experience beyond the cert dives.

 

[boulderjohn]

A very premature question in my list of questions but - Where does one go to obtain the required number of dives to get to some of these teaching levels?

I spent a month in Cozumel finishing PADI divemaster, I'm going back for three months there interning for IST - there's a lot of people flowing thru there so it makes it easier to gain some experience.

I'm looking at tech training to be able to lead "light" deco dives in Cozumel, possibly even teach, as this is where I think I want to call home.

I have a local shop that is SSI - I'm not real clear on the politics behind the scenes but he's pushing TDI, but there really just isn't the availability, or better said, he isn't available to dive enough to gain experience beyond the cert dives.

You may well have to travel to do it.

I live in Colorado, but I went to Florida to get my TDI rimix certification and TDI instructor certification, and I went to Florida to do my PADI crossover. As for getting the dives in between, I went to many different places for those, chiefly Florida and New Mexico.