The Fine Art of Decompression

[SeaJay]

Okay, please no flames on this thread. I can't tell you what to say or what not to say, but I'm asking everyone to please be nice. I have a question about deco that's surely liable to start a flame war (again), so please resist it if you can.

My question is to the more experienced DIR divers.

I'd like to learn how to handle a situation where I've overstayed my NDL. Yes, I know... Plan the dive and dive the plan. Okay, let's say that I PLAN to overstay my NDL. Let's say, for example, that I've got a max depth of 85' and that I'm breathing EANx, according to the tenants of DIR.

Who's the right people to learn this from? Does GUE teach this in Tech I? Is that my next goal?

Of course, I've considered taking the Hal Watt's Deep Air course... But the whole concept of "Deep Air" seems very anti-DIR, and I'd like to stick to GUE standards. Besides, I'm not really interested in "Deep Air." What I'm interested in is learning how to stay under for extended periods of time at shallow depths. What I want to learn is the art of deco.

For example, let's say that I wanted an hour and twenty minutes at 85'. No doubt I'd be using EANx, according to the tenants of DIR. However, that's still past EANx's NDL.

Who do I go to for this training, and where are classes offered?

 

[bwerb]

I think that one of the definitions of technical diving is diving in which decompression obligations are encountered, hence you are not able to ascend directly to the surface.

I always understood that any diving which involves decompression requires technical training. Since you are looking for DIR answers, then I would assume that GUE Tech 1 would be the next step. I don't believe that overstaying your NDL's on purpose without training would be considered DIR in any sense of the term.

So...time to sign-up for the next class.

 

[Waterlover]

Sign up for Tech 1 you'll learn all about it.

 

[leadweight]

Disclaimer: This is not a how-to on deco diving.

Just for fun I ran an 85 foot for 80 minutes profile through v-planner on ean 36 to see what would pop out. Settings were at the default, which include a rather generous .6 cubic foot per minute RMV.

2 minute stop at 20 feet
12 minute stop at 10 feet
183.2 cubic feet of gas consumed
CNS total 43.8%

The gas requirement is way up there and the CNS is, from what I understand, high.

Anyone want to comment on the right way to execute this dive?
Just as an exercise, I don't expect to do it anytime soon.

 

[SeaJay]

Okay, I know it sounded like a dumb question, y'all, but thanks for the answer. Yeah, it looks like I'm craving Tech I.

Okay then... I feel like I did a really lousy job at DIR-F, and I don't personally feel that I can go to Tech I until I've mastered DIR-F. Cool. That's a great "yardstick" to tell me whether or not I feel I'm ready... And I don't.

Okay then... I have one more gear issue to handle, and some more practicing to do. I need some pool time, I think, where I'm dealing with zero current and I can see.

Then, once I am sure of those skills, I'm taking DIR-F again. At the instructor's recommendation, I'll sign up for Tech I.

Sounds like a great course of action. Thanks a lot, y'all.

How exciting... :mean:

 

[SeaJay]

That's pretty interesting. Of course, like you, I won't be doing this dive anytime soon, since I'll get the training first.

But for reference, what are the deco obligations on that same profile when that diver uses air instead of EAN36? EAN32?

 

[wetlettuce]

Hi Seajay

Using Jplan on my Palm doing a 30 mtr dive for 80 mins on air gives you a runtime of 216mins !!! This was using a gradient factor of 30/90

On 32% with 50% deco you get a runtime of 122 mins which is still quite high for ocean dives.

Using 36% will put you ppo2 level to 1.44 which exceeds the 1.4 limit.

If you want to play with deco times and different gasses etc. Vplanner is free and pretty easy to use. www.v-planner.com. If you're going to do Tech1 you don't need to pay for any software as you are shown how to plan the dives on the course without computers or software programs.

Diving to 44mtr (140 ft ish) is covered on Tech1 as well as single stage diving and deco calculated on the fly. You'll need some experience with twinsets and I would recommend you use twins for your DIRF course. I'd only done 5 dives in twins before my DIRF and it was good not to have to break any bad habits and sort out trim and buoyancy with the advice of the instructor. It made a big difference.

Hope that Helps

WL

 

[SeaJay]

It sure does, man... Thanks a lot... That's great information!

I didn't know that V-planner was free! It's now installed on my 'puter! Thanks for that tip!

Okay, then... I'll practice with doubles. I can't tell you how much I appreciate your help...

 

[100days-a-year]

Leadweight and others concerning the above profile.PLEASE take a class before attempting any of these dives.~.6cuft min. is way low for new diver in doubles and with at least 1 stage.I've seen mentioned elsewhere at least 1cuft min. as a baseline .You really got no buisness doing these dives til you can plan your actual RMV and can run tables and software.Read the disclaimers on the VPlan.An actual understanding of all parameters .Depth,narcosis,gas mixes and consumption,dive planning,gear&rigging are all covered in any decent decompression oreinted class.SeaJay you've been here long enough to know better than asking not to be flamed in a discussion where DIR practices are being discussed.People on both sides are very impassioned about thier beliefs.

 

[SeaJay]

100days-a-year once bubbled...
SeaJay you've been here long enough to know better than asking not to be flamed in a discussion where DIR practices are being discussed.People on both sides are very impassioned about thier beliefs.

Pfffttt... Isn't that the truth!

I'm still crispy from the last discussion. Someone said, "What's GUE say about ______?" and I replied, "Hey, I just learned that. They say, '_____'." And I was completely attacked! They didn't agree with the GUE message, and so they strung me up, calling me an "egoist." My gosh! Hey, guys... I didn't write this stuff!

Today I'm nursing my wounds with some Solarcaine. I was just hoping that I could ask this question without going up in smoke again!

It's looking good... :crispy: