Can anyone offer some constructive advice on gas management for extended range 
diving (ie accelerated deco air dives using nitrox) when multi-leveling the 
dive.

I currently use twin 10ltr 300bar steel tanks, manifolded and adopting 
"Hogarthian" principles (ie long hose, no stuffing etc) and use a 10 ltr 
300bar steel tank for EAN80 from 9m upwards.

The diving I do of this nature is always when exploring wrecks. Up till this 
point in time I have always dived rule of thirds on my twinset and 50% + 15bar 
EAN80 reserve.

Given the separate deco gas source I now use (as opposed to just having a 
twinset of air) I believe I am quite safe to breath my air down to 50% (150 
bar) before beginning my ascent. I have run many dive profiles etc with 
ProPlanner and everytime I have enough air to deco should the EAN80 fail.

The tables I have cut and take down are for single depth only. So if I should 
briefly journey to say 50m then spend the rest of the dive at 35m I have to 
assume a square 50m profile for the deco schedule I then execute. Nothing new 
with that I know. 

So far so good. But given I am going to dive to 50% reserve on my bottom time, 
it is possible on the above profile that I could leave myself with 
insufficient air in an EAN80 failure to complete the air deco schedule. Albeit 
that the longer deco is due to briefly visiting 50m and not therefore actually 
essential, however apart from taking down my notebook PC I'm not sure how to 
get round this without compromising my safety margin which is allowing for one 
reg failure in my configuration.

I'm looking for constructive/intelligent advice here. If you cant manage that 
and are one of the pyromaniacal flamers on this list please put yourself out 
with a big dive on a small cylinder.

Many thanks
Lawrence D. Orchard
BSAC Advanced * TDI Extended Range * PADI DM601001
Tel/Fax: +44 (0)1483 420755
Email: DiveBase@ms*.co*
"Who's the more foolish ?  The fool or the fool who follows him"

Navigate by Author: [Previous] [Next] [Author Search Index]
Navigate by Subject: [Previous] [Next] [Subject Search Index]

[Send Reply] [Send Message with New Topic]

[Search Selection] [Mailing List Home] [Home]