Deco gas for pony

[Ben Harris]

Defo, I did my Basic Nitrox a few weeks ago with Andy and everyone else. It was a great course and the diving / training was very good. I was doing basic nitrox to make up a segment of the SDI Advanced program. I cant wait to do advanced nitrox and the deco course.

[Mark]

Kirky,

post dive fatigue can more than likely be attributed to sub-clinical DCS. You can go a long way to reduce this by slowing down your ascents. Stick to 10m/min and do you safety stop @ 6m (not 5). From 6m to the surface go at 1m/min (so take 5mins to reach the surface after your 6m stop). You should notice a marked improvement (even on air :reaper: ) if you do this. One thing you should also (always) do is stay horizontal during your ascents and deco.

Obviously using nitrox as backgas will help you a lot. If you were using 36% as backgas for your 18m dive, there would be no real point switching to 40% for your 6m stop. If you switched to pure O2 it would make a difference but would be over the top.

Have a look at this - http://www.fullcave.com/oxygenwindow.htm

40% is not a great deco gas - 50% is much better.

Dunno if that will help or not  - It's all pretty standard stuff so maybe :outtahere:

Mark

look at all those edits lol





(Edited by Mark at 1:50 pm on Dec. 4, 2002)


(Edited by Mark at 1:55 pm on Dec. 4, 2002)


(Edited by Mark at 1:59 pm on Dec. 4, 2002)

[JohnK]

Mark - some good points - I try to stick to the basics in terms of ascents but will slow it down a bit further. As far as the 50% is cincerned - this was what I was advised but can only currently go for 40% due to certification - something for the list next year I think !!

Thanks to all for the feedback

[Mark Chase]

Just to step right in with a controversial statement for my first post:

40 02% will give a P02 of 1.6 at 30m which is more than acceptable risk for bail out as long as the diver is calm and in practice. The P02 at 40M is apx 2 which qualifies under the NOAA exceptional exposure tables as a 30mn max exposure limit??. So I would happyly bail out to 40% at 40m and start to ascend immediatly.

CNS limites are time dependent and of course condition dependant so I feel that a bail out and immediat ascent at 10m/min to 30m is an acceptable risk. I use 1.6pp for deco all the time and switch to 50% at 21m and 80% at 9m.  

Mind you you shouldent be at 40 with anything less than a twin set IMO

Mark Chase  

[Andy Winterburn]

Kirky
If you send me an email I'll send a spread sheet with the O2 depths V CNS shown, then you can quickly decide the mix you want to use
andrew@kasian.force9.co.uk

[JohnK]

Hiya folks - thanks to all for the info - its amazing how views differ !!

I`ll still put a high mix in the pony for shallow deco only - not for bailout at depth - thats what (hopefully) the twins will cover.


(Edited by kirky at 6:51 pm on Dec. 8, 2002)

[Mr T.]

Hey Kirky,

I was at Dales's house yesterday with Davey and saw your brand-new Twin-set sitting there.....all sparkly and new.....and saying to me...."Please take me somewhere wet and dive with me....."

Seriously mate, they look the Nads. Enjoy em and hope to dive with you soon.

[Davey Willo]

They were there but wot with me being a thieving git I've had em away..

Psst!! mister, wanna buy a twinset?

Bren's right kirky me ol'mate.. they look luverly, all shiney and nice like...

[JohnK]

All I can say is WOOOOOOOOHOOOOOOOOOOOO!!!!!

Off to Cape next Sat to try them out - picking them up Tues pm. Cant wait.

I`ll be dusting them for prints so be warned !! - Oh how I`ll cry when the first scratch appears. I`ll be at the Dotty gig in January and hope to meet up with some of you guys - Only met John H & Ben to date and they are good folk - especially John when he`s effin and blindin !!

If anyone fancies another Cape bimble next Saturday give me a shout. Was in the Dock today assisting a rescue course - 10m of vis - luxury - but gettin bloody cold at 7 degrees.

Cheers all

[Davey Willo]

I'm up for a meet on Saturday..  :biggrin:

kirky, I'm afraid the tanks will be scratched straight away, but hey mate, you don't really wanna look like Mr Burton shops window man now do ya..

Ok so anyone else up for a day of rig trimming and skill sets?