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Here Why Deep Stops make sense

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Here Why Deep Stops make sense

Postby eDiver » Fri Mar 23, 2012 6:22 pm

Few days ago I was reading a very interesting article THE FIVE WAYPOINTS AND SIMPLE ASCENT BEHAVIOR by Steve Lewis (aka doppler) that, among other things, was discussing the concept of off-gassing ceiling and how to use this entity to determine the "Deep Stop" that marks the first step in Steve's 5 points ascent strategy.

I actually took the RD class some time ago and I had already red Baker's article on Deep Stops .... basically he is saying "use Gradient Factors" ..... and we do have GF implemented in divePAL

But, how do we determine this magic deep stop?
Can we calculate it with a formula? Or is it an empirical construct determined with experience?

I asked the team to add to divePAL a new tool: the Off-gassing ceiling grapher :D
and I am going to use it to visualize - instant by instant - the off-gassing ceiling for each compartment during a test dive done with ZH-L16C and GF 100/100.

Surprise .... surprise .... the resulting graph is a clear visual demonstration that deep stops ARE a good idea.
Why? Just look at the image below.
At my first stop (12m) there is a whopping 2.81atm overpressure gradient in C2 (that is still sitting at 40.1m). That seems a lot to me.
The other interesting factor in this graph is the almost artistical nature of the ZH-L16C algorithm; do you see how the leading compartments change in progression as the diver is ascending?


So, ascending too shallow it seems to NOT be a good idea. We need Deep Stops .... but, where do we stop then?
And, are the stops provided by GF the best ones?
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