The math behind Haldane, Buhlmann, RGBM, and VPM algorithms?

[DiveNav]

You added that? Nice!!!

Yes we did

.....Now, how about my Uwatec Smart Pro and all my VR-3's?

No plans for those .....

Alberto (aka eDiver)

 

[lowviz]

...//...No plans for those ..... ...//...

Yeah, I know.

Anyway, kudos on the offgassing ceiling stuff. Maybe now a few divers will come to realize the importance of same.


-posted as I am still secretly hoping VR technology will start bugging you guys... (before they fold)

 

[DiveNav]

.....posted as I am still secretly hoping VR technology will start bugging you guys......

We did contact them a year or two ago .... they were not interested then ... and they are still not interested now.

But ... we did put the DG05 (Hollis version of the VRx) in our simulators

Alberto (aka eDiver)

 

[rongoodman]

I just flipped open my copy of Wienke's "Basic Decompression" and quickly ran across some partial differential equations--a little beyond first year calculus.

 

[boulderjohn]

I had an interesting experience last week that compares different algorithms. I was tagging along with a class on a decompression dive planned to 300 feet. The students prepared a plan very carefully using V-Planner. They were also using their computers (Liquivision) for backup. I used a Shearwater Predator (Bühlmann) for backup. The Shearwater allows you to plan ahead of time, so I inputted the gases and the bottom time to see how it would differ from V-Planner. The difference was huge. Following my computer would have taken me shallower much sooner and gotten me out of the water much earlier.

I stayed with their plan and watched how my computer kept adjusting as we ascended. The only time I departed from their plan was staying at the 30 foot stop a few minutes longer. When we completed the final planned stop, my computer cleared at almost exactly the same time as the V-Planner plan was completed.

 

[lowviz]

??? -was everybody using the same level of conservatism?

 

[boulderjohn]

??? -was everybody using the same level of conservatism?

I know what level of conservatism was used on the V-Planner planning. The Shearwater does conservatism differently. I frankly didn't care. I had no concerns about following the V-Planner schedule--I have done it often before. My computer was just an emergency backup. As I said the Shearwater uses a different decompression theory, so it is bound to be different. The Shearwater keeps adjusting, and it does not care if you choose to follow a different plan during the dive.

 

[lowviz]

Understood, but it is much easier to compare DC's when they are all set to zero.

A high level of supersaturation, just before bubbling, speeds your exit. However, I prefer to avoid such.

When my dive is done I like to boogie up to the off-gassing ceiling and hang for a few. Then keep my supersaturation level effective, but kinda low. I'm old, I've got lots of time...

 

[Karl_H]

I had an interesting experience last week that compares different algorithms. I was tagging along with a class on a decompression dive planned to 300 feet. The students prepared a plan very carefully using V-Planner. They were also using their computers (Liquivision) for backup. I used a Shearwater Predator (Bühlmann) for backup. The Shearwater allows you to plan ahead of time, so I inputted the gases and the bottom time to see how it would differ from V-Planner. The difference was huge. Following my computer would have taken me shallower much sooner and gotten me out of the water much earlier.

I stayed with their plan and watched how my computer kept adjusting as we ascended. The only time I departed from their plan was staying at the 30 foot stop a few minutes longer. When we completed the final planned stop, my computer cleared at almost exactly the same time as the V-Planner plan was completed.

Sounds like GF vs VPM - I often dive with a friend who uses a Predator while I use a X1 running V-Planner, if we dive OC and we extend our deeper stops around gas switches the X1 always clears before the Predator, on CCR with the same set-up and no extended deeper stops the Predator normally clears around the same time, or slightly quicker (we're talking 1-2 minutes) quicker than the X1.

Don't forget the pre-generated plan on V-Planner was likely to be longer than the actual schedule needed by the V-Planner live on the X1. It always seems like the GF models seem to go on strike once a new ceiling is available and doesn't give much credit until the new ceiling depth is reached?

 

[Red Sea Shadow]

Anyone have any good resources about the topic?

There are articles on decompression and some of its algorithms in the different issues of Tech Diving Mag. Also there's a decompression software called Ultimate Planner incorporating both VPM and Buhlmann algorithms.