Lost deco gas planning question

[Janos]

I'm not sure I understand the question. Is it that you have enough backgas to get you out of the water with NO deco gas, and you're wondering what stops to do if you do some of your deeper stops on 50% then your 50% stage fails.

If that's your question then I'd just follow the plan up on my lost deco gas plan, ignoring the fact that I'd done some stops on 50%. After all, what's a few extra minutes?

Janos

[dave archer]

Garf, I agree, you can't plan for everything and I accept that, the only 100% safe way to dive is to not dive. And you can carry too many plans, so I'm going to drop my Deeper plan and my Longer plan, and just carry the Deeper and Longer plan, to be used if we do either. But this scenario I've (rather badly!) outlined is something that could feasibly happen and is easy to plan for, I just wanted to make sure I know what my plan for it is.

Mark, re Helium, I'd quoted 30min @ 45m incorrectly last night, I'd had a few beers and was thinking of my Deeper plan. Actual planned dive is 30mins @ 40m. Sure, even then some He would be preferrable, but I'm not trained in He yet, and want to get a reasonable amount of "simple" accelerated deco under my belt before I do my mix ticket next year (not to mention some more spondoolies in my empty bank account )

Re an OMG plan for if I find myself short of gas, it's not quite what I was asking but I like that idea and will work one up, thanks. What planning software do you use. I use VPlanner on VPM-B +2 conservatism. If I change it to +0 to get an OMG plan it doesn't give me a plan that much more aggressive (40 min ascent on +0, versus 47min ascent on +2)

Janos, you're right that's exactly the question I was trying to ask about, except I was looking at if from the other angle - I wasn't considering whether I could shave time off the remaining stops on the Lost Gas plan, I was wondering if having done shorter deeper stops than the LG plan calls for I might be advised to extend the shallower ones, or whether the fact the stops done so far were on 50% made up for their shorter nature enough. Logically I guessed it would, but deco is a funny business, hence the question.

Anyway, it's clear now - just switch to Lost Gas plan and follow it for remaining stops. Extend if want but not required.

Phew - I really must make sure I ask the right question up front next time!

Thanks everyone,
Dave.

[Janos]

Originally Posted by dave archer

Janos, you're right that's exactly the question I was trying to ask about, except I was looking at if from the other angle - I wasn't considering whether I could shave time off the remaining stops on the Lost Gas plan, I was wondering if having done shorter deeper stops that the LG plan calls for I might be advised to extend the shallower ones, or whether the fact the stops done so far were on 50% made up for their shorter nature enough. Logically I guessed it would, but deco is a funny business, hence the question.

If you follow Bulhman based deco, then yes, shallower stops will be as per your lost gas plan. OTOH if you believe bubble models, then theoretically there may be a small discrepancy, but I really wouldn't worry about. What you had for breakfast will affect your deco more.

Janos

[Mark Chase]

I run GFs in Deco Planner.

ATB

Mark