Deco Question

[rustuk]

This might be in the wrong area, but hey ho..

Had a very nice couple of dives off Bridlington on Monday.
During the first dive I notched up a couple of minutes of deco - no biggy; my computer sorted everything out - I.E How long, what depth to do it etc.

But.
I'd like to be able to actually plan for this, so my question(s) is/are:

Is there a reasonably simple formula to work out deco planning, or tables available to equate depth/times to deco time/depths.

95% of my diving is never going to touch deco, but I'd like to know more and be able to work out any potential deco beforehand.
To be honest, I'd just like to know how it all works..

Cheers
Russ.

[IanD]

Brace yourself

[rustuk]

Originally Posted by IanD

Brace yourself

Yeah I know - I feel a world of pain coming on...!!

[thewisestfish]

Just make sure you stay above me when I'm digging in the dirt trying to be brave enough to grab a lobster. I bet you regret asking that question Mr A. I bet you my next lobster.

[SoggyFox]

i shall be first.............take a course, not sure what certs you've already got, but theres enough good instructors out there that would help and advance your diving to boot.

[Woz]

Christ. I'd run and hide somewhere. Was this not covered in basic training? If you're BSAC then you need to do the Sports Diver qualification.

Unless you're taking the piss.

[SML]

With Suunto computers you can 'plan' the dive to give you a max bottom time

[rustuk]

Originally Posted by Woz

Christ. I'd run and hide somewhere. Was this not covered in basic training?

Partly..
Obviously there's all the PADI RDP stuff which (as you'll know) gives you all the NDL stuff - but not (unless I slept through that bit) exceeding NDL by X = Y minutes at Z depth etc.

And this is what I'm interested in..

[Mal Bridgeman]

Might be slightly controversial....but

It's generally accepted by those that do a lot of deco diving that using "normal" dive computers to manage the decompression is not a good idea. The "shape" of the deco profile is not optimum.

That said they are generally regarded as quite conservative and I think most people would agree that so long as you don't have pre-disposing factors like de-hydration, poor fitness etc, then up to 10 mins of deco on a dive computer is not a big issue.

More than that and you really need to start thinking about additional training associated with an overhead environment and increasing your diving proficiency to be able to hold stops accurately ... this affects the efficacy of off gassing. There are a range of options depending on your preferences. During these courses you get introduced to things like software planners and with some instructors/agencies some mental calculations to be able to do this without a computer.

It is important when "notching up" deco to ensure you have enough gas to do the deco and, if necessary, get your buddy up as well.....if that sort of thing is important to you.

Again gas planning is covered on those courses.

HTH
Mal

[Woz]

Well- you can do a search on the Interweb for Buhlmann tables but frankly I'd do the course. What Mal says about computers though- up to 10 mins is fine but beyond that I pad the deco by using another richer deco mix and coming up slowly from 21m. Alternatively make it up as you go along using Deco on the Pie.