Algorithms

[Doppler]

Another request for information.

The question is primarily aimed at experienced decompression divers who regularly conduct dives that net decompression obligations that exceed bottom times.

Thanks

DD

[WreckWriter]

I prefer VPM, through V-Planner. Deco pretty much always exceeds BT.


WW

[WYDT]

I assume you've seen GI's deco explanation?....

This site has a lot of good links to them... if you can stand the blue on black colors....

http://www.diveventures.com/Techinfo.htm

[Doppler]

WYDT once bubbled...
I assume you've seen GI's deco explanation?....

This site has a lot of good links to them... if you can stand the blue on black colors....

http://www.diveventures.com/Techinfo.htm

I'm not sure why you'd assume that, :) but I've known George for a while and am aware of most of the practices his group has adopted and developed over the past seven or eight years. I will look up the site and read when I have a chance.

I am more interested in the results of a simple straw poll to get a sense of what the tech community as a whole are using and if this small sample here indicates congruence with the larger trend. Although we don't have access to a captive test group diving a standardized profile on standardized gases, I think the results may be useful... in fact the sample group may be more valid because of the apparant variety of users on this chat group.

thanks

DD

[Divesherpa]

I was Buhlman, but now I'm bubble. I feel much better after the dive and enjoy the deco much more. I've finally converted to 30 second stops and it really helps.

[WYDT]

Doppler once bubbled...


I'm not sure why you'd assume that, :) but I've known George for a while and am aware of most of the practices his group has adopted and developed over the past seven or eight years. I will look up the site and read when I have a chance.

I am more interested in the results of a simple straw poll to get a sense of what the tech community as a whole are using and if this small sample here indicates congruence with the larger trend. Although we don't have access to a captive test group diving a standardized profile on standardized gases, I think the results may be useful... in fact the sample group may be more valid because of the apparant variety of users on this chat group.

thanks

DD


Yes, it would definitely be interesting.... one thing of particular interest on that site I linked to are graphs that show the difference in the deco curves between what George does and what the software calls for. I believe the software in this case is decoplanner using Bulhman ZHL 16b though the gradient factors used are not given.

DSAO!

[MikeFerrara]

Question...

GI says the 20 ft stop plus the ascent should at least equal your bottom time. None of the profiles given seem to do it that way. What am I missing? How is he figuring his time at 20 ft? On the 170ft foe 20 min he is only spending like 10 min. The 130ft foe 45 min also seems to have a 20 ft stop and ascent far shorter than the bottom time. I'm comfused.

I currently use D-plan. I like Vplanner but I am not going to carry a lap top. The palm is the way to go. We make some alterations to the schedule like shortening stops before gas switches but I don't change the 20 ft stop much for the reasons stated above.

[Doppler]

MikeFerrara once bubbled...
Question...

GI says the 20 ft stop plus the ascent should at least equal your bottom time. None of the profiles given seem to do it that way. What am I missing? How is he figuring his time at 20 ft? On the 170ft foe 20 min he is only spending like 10 min. The 130ft foe 45 min also seems to have a 20 ft stop and ascent far shorter than the bottom time. I'm comfused.

I currently use D-plan. I like Vplanner but I am not going to carry a lap top. The palm is the way to go. We make some alterations to the schedule like shortening stops before gas switches but I don't change the 20 ft stop much for the reasons stated above.

Mike: someone else may be able to interpret George's advice... I can't because I haven't read the latest stuff from WKPP... can you cite the place from which you drew your quote?

Mike, you might also be interested to know that v-planner is available for the Palm. I do carry a laptop with me -- hey, look what I do for a living, I'm a nerd -- but find the palm version is handy to have if I need any more info than is in my Wetnotes...

Take care... hope someone can give you an answer

DD

[MikeFerrara]

The info I have is right from the WKPP site and is also on the site that WYDT provided. I think his explaination is clear enough but the example profiles don't seem to match at least as far as the 20 ft stop and ascent to the surface.

I'll have to get the palm version of Vplanner.

[O-ring]

MikeFerrara once bubbled...
The info I have is right from the WKPP site and is also on the site that WYDT provided. I think his explaination is clear enough but the example profiles don't seem to match at least as far as the 20 ft stop and ascent to the surface.

I'll have to get the palm version of Vplanner.
If it does, we can post it..

[MikeFerrara]

I don't have any deco software with me. I'll have to wait till this evening to try it.

[O-ring]

MikeFerrara once bubbled...
I don't have any deco software with me. I'll have to wait till this evening to try it.
...if you want to know now you can PM me the profile stuff..

[MikeFerrara]

O-ring once bubbled...

...if you want to know now you can PM me the profile stuff..

Run some variations of the 170 for 20 example profile on the link that WYDT provided to see if you can approximate the 20 ft stop time. Also, GI's isn't using any software is he?

[O-ring]

170 20
110 1
100 1
90 1
80 1
70 1
60 1
50 1
40 1
30 2
20 9
20 to surf 6
0

I noticed he lengthened his 70' stop to let that 50/50 get in there...looks like he is stopping for about 3-4 mins.

Nevermind, I can't do it...I tried lengthening all those stops in the middle to 3 minutes like GI is doing, but that screws up the 20' stop. He has to be modifying the decoplanner output (IMHO). If I stick to the 20' stop I got originally, that looks like the tail end of his deco. If I then decide to spend 3 minutes at each stop from 70' until 20' instead of the decoplanner 1 minute stops, it looks pretty close. But...why would he be doing that? Is that just a really molasses slow ascent?

[WreckWriter]

What mix and what deco gasses did you use?

[WreckWriter]

V-Planner 3.10 by R. Hemingway, VPM code by Erik C. Baker.

Decompression model: VPM-B

DIVE PLAN
Surface interval = 2 day 0 hr 0 min.
Altitude = 0ft
Conservatism = Nominal

Dec to 170ft (3) on Trimix 18.0/45.0, 50ft/min descent.
Level 170ft 16:36 (20) on Trimix 18.0/45.0, 1.11 ppO2, 62ft END
Asc to 100ft (21) on Trimix 18.0/45.0, -60ft/min ascent.
Asc to 90ft (21) on Trimix 18.0/45.0, -30ft/min ascent.
Stop at 90ft 0:30 (22) on Trimix 18.0/45.0, 0.67 ppO2, 25ft END
Stop at 80ft 1:00 (23) on Trimix 18.0/45.0, 0.62 ppO2, 20ft END
Stop at 70ft 5:00 (28) on Nitrox 50.0, 1.56 ppO2, 32ft END
Stop at 30ft 3:00 (32) on Nitrox 50.0, 0.95 ppO2, 7ft END
Stop at 20ft 10:00 (42) on Oxygen, 1.60 ppO2, 0ft END
Asc to sfc. (42) on Oxygen, -30ft/min ascent.

Off gassing starts at 130 ft

OTU's this dive: 56
CNS Total: 37.2%

84.3 cu ft Trimix 18.0/45.0
11.8 cu ft Nitrox 50.0
8.2 cu ft Oxygen
104.3 cu ft TOTAL


DIVE PLAN COMPLETE

[O-ring]

WreckWriter once bubbled...
What mix and what deco gasses did you use?
It was 170' for a 20 min BT with 20/35 as a bottom mix...using only 50/50 for deco. They were messing around and trying to emulate one of GI3's curves on that website posted earlier in the thread...I got interested and tried it.

[MikeFerrara]

I was just trying to use the procedures GI outlines in his articles to recreate the example profiles he gives and I can't duplicate them.

[O-ring]

MikeFerrara once bubbled...
I was just trying to use the procedures GI outlines in his articles to recreate the example profiles he gives and I can't duplicate them.
He says in the first article to do your first stop at 80% of the max depth in ATA rounded up... so at 170, that's about 6 ATA * .80 = 5 ata = 130'. His first stop on the graph is at 120'...

Here's something of his I found about doing dives in the ~170' range (http://home.earthlink.net/~toddclagett/decocurves/DecoCurves.htm)

I would make the following changes: slower decent, then after 20 at the
bottom, ascent at 30 fpm, consciously stopping every ten feet to achieve
this, then stop at 120-80 for 30 seconds each.

At 70, the gas switch, I would do 3 minutes to get the full effect of the
switch. See the post that talks about circulation time.
The 3 minutes each at 60,50,40
5 at30
8 at 20
ascend to 0 in 3 minutes

I notice you make a comment about the line. Get in the habit of consciously
stopping every ten feet to insure the proper ascent rate. Coming up from
depth too fast is what gives you the subclinical symptoms hours after the
dive. You trap gas in poorly perfused areas and these later swell and react,
the bubbles in them grow, the reaction presses on nerves, and you get things
like numbness in some extremities while you are sleeping that night - not a
cns hit, a cns manifestation. Skin bends would be a more obvious consequence
of skipping deep stops.

[WreckWriter]

O-ring once bubbled...

It was 170' for a 20 min BT with 20/35 as a bottom mix...using only 50/50 for deco. They were messing around and trying to emulate one of GI3's curves on that website posted earlier in the thread...I got interested and tried it.

Odd mix. here's what V-planner gives. note the off gassing point is said to be 124.5':

Dec to 170ft (3) on Trimix 20.0/35.0, 50ft/min descent.
Level 170ft 16:36 (20) on Trimix 20.0/35.0, 1.23 ppO2, 83ft END
Asc to 100ft (21) on Trimix 20.0/35.0, -60ft/min ascent.
Asc to 90ft (21) on Trimix 20.0/35.0, -30ft/min ascent.
Stop at 90ft 0:30 (22) on Trimix 20.0/35.0, 0.74 ppO2, 37ft END
Stop at 80ft 1:00 (23) on Trimix 20.0/35.0, 0.68 ppO2, 31ft END
Stop at 70ft 5:00 (28) on Nitrox 50.0, 1.56 ppO2, 32ft END
Stop at 30ft 2:00 (31) on Nitrox 50.0, 0.95 ppO2, 7ft END
Stop at 20ft 12:00 (43) on Nitrox 50.0, 0.80 ppO2, 1ft END
Stop at 20ft 5:00 (48) on Trimix 20.0/35.0, 0.32 ppO2, 0ft END
Stop at 20ft 1:00 (49) on Nitrox 50.0, 0.80 ppO2, 1ft END
Asc to sfc. (49) on Nitrox 50.0, -30ft/min ascent.

Off gassing starts at 124.5 ft

[O-ring]

Run decoplanner at GFLo 5 and GFHi 100 for said profile

170 20
110 1
100 1
90 1
80 1
70 1
60 1
50 1
40 1
30 2
20 4
10 9
0

Drop the 20’ stop and do the 10’ stop at 20’

170 20
110 1
100 1
90 1
80 1
70 1
60 1
50 1
40 1
30 2
20 9
0

then after 20 at the
bottom, ascent at 30 fpm, consciously stopping every ten feet to achieve
this, then stop at 120-80 for 30 seconds each.

170 20
120 :30
110 :30
100 :30
90 :30
80 :30
70 1
60 1
50 1
40 1
30 2
20 9
0

At 70, the gas switch, I would do 3 minutes to get the full effect of the switch. See the post that talks about circulation time.
The 3 minutes each at 60,50,40
5 at30
8 at 20
ascend to 0 in 3 minutes

170 20
120 :30
110 :30
100 :30
90 :30
80 :30
70 3
60 3
50 3
40 3
30 5
20 8
0 3 minutes to surface

Runtime = approx. 50:30.. plus ascent from 170-120 = 50' @ 30 fpm = roughly 1.5 minutes = 52 mins?

Getting closer...but why modify it this much?

[Doppler]

A couple of points that have been raised here... worth talking about although slightly off topic for the poll ;)

Spiking the O2 on gas switches... something we have found very effective using V-planner for mix dives in Great Lakes conditions and one of the user editable variables in the program set-up. Setting a rest on gas switches for 4 minutes above 100 fsw (the switch at 70 feet for instance) and for 3 minutes below 100 fsw that is. Spiking the oxygen in this way seems to have a beneficial effect (purely subjective observation) and in theory manages the vacant partial pressure opportunites in the most efficient way.

Setting gradient factors in Decoplanner to 5 and 100% trying to emulate a schedule posted by GI. Couple of things here in fact. Firstly, Erik did some stella work modifying Dr. Buhlmann's work to follow the deep stop imperative, and by whittling at the MValue presets and getting them away from default values, it's possible to get a profile that's very dissimilar to the "standard" one... in fact it follows quite closely -- especially in short exposures to the 200 foot range on standard mixes -- the profiles kicked out by bubble model algorithms....

It just seems more logical to me to use the bubble model algorithm in the first place... My bias is showing and I don't want to prejudice the poll, but I have a strong sense that the bubble theory with its premise "There are bubbles in the blood, let's deal with them, here, deep, now" models more closely what might seem to actually happen in the diver's body... rather than making radical changes to a dated premise to make it behave in a similar way. And I say this with regrets since Buhlmann is one of the unsung heroes of modern diving.

20 foot stops and ascent times... I have not read the posting that people are quoting from George, but unless he has radically changed his mind over the past couple of years, when I last talked to him, we sort of agreed that long 20 foot stops on oxygen where unnecessary and presented the potential for nasty outcomes. It would be better to deal with the offgassing necessities deeper and then spend the shortest time possible on O2 then ascent gently and get out of the water... any further oxygen therapy can take place in comfort on the surface.

OK that said... trying to emulate his profiles with the copy of decoplanner you bought from EE will likely not work. To begin with, he isn't using it. Also, what sort of profiles is he talking about? Does he specifically cite a depth, time and gas mixes? Perhaps his statement has been taken slightly out of context and he is making a general statement... the jist of which is "Don't spend ages at 20 feet."

The long 20 foot stops are a simple hang-over from earlier interpretations of decompression theory that "fixed" the massive bubbling picked up by rushing or ignoring the need for slow acsent through the deep part of the water column. This 20-foot oxygen therapy still did not fix everything and we had a whole generation of divers who were told that "Silent bubbles are OK" Bull****... silent bubbles mean you have sub-clinical decopression. Your schedule was wrong. What they were telling us is change your thinking! We only started to listen recently.

DD

[Ari]

Looks like it provides a little more margin for error, especially for repetitive dive series.

Ari :)

[wb416]

Doppler once bubbled...
[snip]

20 foot stops and ascent times... I have not read the posting that people are quoting from George, but unless he has radically changed his mind over the past couple of years, when I last talked to him, we sort of agreed that long 20 foot stops on oxygen where unnecessary and presented the potential for nasty outcomes. It would be better to deal with the offgassing necessities deeper and then spend the shortest time possible on O2 then ascent gently and get out of the water... any further oxygen therapy can take place in comfort on the surface.
[snip]

DD

Doppler,
I think the concept that some are working through here (how GI3 manipulates "the plan") is summarized in part of an address that he gave to a group in California May 2002.

He basically summarized what you've presented in regards to maximumizing the "Oxygen Window" and the stops closest to the gas switches. He seems to be "massaging" time away from stops that have the lowest benefit to those with the highest pPO2. However, he notates that on the stop just prior to a gas switch he drops back to back gas to "buffer" his system against the higher pPO2 at the switch, and also allow him to sit there longer, maximizing the inert gas/O2 gradient.

Deco, Deep Stops, O2 Window (http://www.baue.org/library/irvine_baue_talk.html#Decompression)

To recap, it sounds like based upon a May 2002 presentation that GI3 is still espousing a philosophy similar to one that he talked with you about, which seems to be "... deal with the bubbles in their infancy rather than attempting to treat the effects of them at later stops..."

Since I'm still trying to get a "firm" grasp on all these concepts myself, feel free to redirect or correct any statements I've made.

wb

[MikeFerrara]

Doppler once bubbled...

OK that said... trying to emulate his profiles with the copy of decoplanner you bought from EE will likely not work. To begin with, he isn't using it. Also, what sort of profiles is he talking about? Does he specifically cite a depth, time and gas mixes? Perhaps his statement has been taken slightly out of context and he is making a general statement... the jist of which is "Don't spend ages at 20 feet."

DD

I have been trying to emulate GI's profile using the procedures he outlines in his articles not with any software. I haven't been able to get close and am wondering what I am missing.

[Doppler]

cwb once bubbled...


SNIP....

He basically summarized what you've presented in regards to maximumizing the "Oxygen Window" and the stops closest to the gas switches. He seems to be "massaging" time away from stops that have the lowest benefit to those with the highest pPO2. However, he notates that on the stop just prior to a gas switch he drops back to back gas to "buffer" his system against the higher pPO2 at the switch, and also allow him to sit there longer, maximizing the inert gas/O2 gradient.

...SNIP
wb

Hey there CWB (i know who you are!!!) Thanks for providing the link... yes, essentially that's it. The major difference between the 'common' bubble model aproach and George's is the dropping of the po2 immediately before the o2 spike. He has stated that this actually accelerates the inert gas outwash... not sure if he cites any studies or not or if he gives some physiological reason... my sense is that if it works it might have to do with surfactant replenishment and vasodilation... but that's a whole other issue and my strong suit -- as you know -- is physics not biology... any other thoughts on that anyone?

I think we also have to remember something important when trying to emulate a profile that works for someone else... at the bleeding edge of any technique or technology, it's easy to **** up. George and any experienced decompression diver knows how to listen to waht their body tells them about the profile they just ran... you get a sense of how close to the edge you got, and if you are sensible know what factors to note and take into account for next time. Decompression algorithms try to model what goes on... but the science is suspect (well, the math actually). A lot of it is art and alchemy.

DD

[O-ring]

I think we also have to remember something important when trying to emulate a profile that works for someone else... at the bleeding edge of any technique or technology, it's easy to **** up. George and any experienced decompression diver knows how to listen to waht their body tells them about the profile they just ran... you get a sense of how close to the edge you got, and if you are sensible know what factors to note and take into account for next time. Decompression algorithms try to model what goes on... but the science is suspect (well, the math actually). A lot of it is art and alchemy.
We were totally doing this as an exercise and personally I would never do any of the stuff in this thread. It was fun playing around with it though..

[MikeFerrara]

O-ring once bubbled...

We were totally doing this as an exercise and personally I would never do any of the stuff in this thread. It was fun playing around with it though..

Agreed. I am just trying to use GI's outlined procedure to see if I can duplicate the profile on paper (I can't). When I dive I cut tables.

[Richeod]

Mike,

The reason you and the others can't duplicate the profile that GI gave is because you're looking at it from the wrong angle. It is not a modified dissolved gas or bubble model profile. It is designed from scratch.
This is an early profile using what GUE has come to call Ratio Deco. This is the famous "deco on the fly" that so many people talk about. It has since evolved to a very easy to understand and even easier to implement system.

Using 21/35 and 50% (close enough to the example) at 170' for 20 minutes I get this profile.

130' 1 minute
120' 1 minute
110' 1 minute
100' 1 minute
90' 1 minute
80' 1 minute
70' 3 minutes
60' 3 minutes
50' 3 minutes
40' 3 minutes
30' 3 minutes
20' 10 minutes
10' 5 minutes

As you can see it is very close to what GI wrote. It took me about 30 seconds to come up with it. Even better is that it works very well.

Hope this sheds a little light on things.

P.S. Please don't ask me how it's done. If you really want to know Andrew G. offers a great class called Tech 1 that covers this and much more.

[O-ring]

Not worth the effort..

[Richeod]

I agree with what you're saying. However, there's more to it. GUE still uses and teaches DecoPlanner. There is more class time dedicated to its use than to Ratio Deco. Ratio Deco works beautifully for what it was designed to do. It is not designed for the diver who decides to do an air dive to 220' and deco on just O2. Nor does it work for the diver wishing to use 17/30 (or whatever) and deco on 80%. It simply wasn't designed to work in every situation. If not used along the lines it was intended it could result in a very bad day. That is why neither GUE nor I will post it on the internet. You need to take the class to see the whole picture.
That being said, GUE teaches a very slick way to use one set of ranged tables (generated using DecoPlanner) to plan all your dives. They can be easily modified on the fly for different depths, bottom times, bottom mixes, and/or deco mixes.
GUE still uses, teaches, and stands behind DecoPlanner. It is a much more versitile tool. More importantly a diver with very little deco knowledge can punch in a profile and get a table that will (most likely) get him back to the boat in decent shape. Kind of important for a program anyone can download from the internet.

[O-ring]

Richeod once bubbled...
I agree with what you're saying. However, there's more to it. GUE still uses and teaches DecoPlanner. There is more class time dedicated to its use than to Ratio Deco. Ratio Deco works beautifully for what it was designed to do. It is not designed for the diver who decides to do an air dive to 220' and deco on just O2. Nor does it work for the diver wishing to use 17/30 (or whatever) and deco on 80%. It simply wasn't designed to work in every situation. If not used along the lines it was intended it could result in a very bad day. That is why neither GUE nor I will post it on the internet. You need to take the class to see the whole picture.
That being said, GUE teaches a very slick way to use one set of ranged tables (generated using DecoPlanner) to plan all your dives. They can be easily modified on the fly for different depths, bottom times, bottom mixes, and/or deco mixes.
GUE still uses, teaches, and stands behind DecoPlanner. It is a much more versitile tool. More importantly a diver with very little deco knowledge can punch in a profile and get a table that will (most likely) get him back to the boat in decent shape. Kind of important for a program anyone can download from the internet.
That makes sense...kinda like the depth averaging thing they do for recreational diving.

Thanks for the info..

[Doppler]

Richeod once bubbled...
Mike,

The reason you and the others can't duplicate the profile that GI gave is because you're looking at it from the wrong angle. It is not a modified dissolved gas or bubble model profile. It is designed from scratch.

>>>>>>>>SNIP

Using 21/35 and 50% (close enough to the example) at 170' for 20 minutes I get this profile.

130' 1 minute
120' 1 minute
110' 1 minute
100' 1 minute
90' 1 minute
80' 1 minute
70' 3 minutes
60' 3 minutes
50' 3 minutes
40' 3 minutes
30' 3 minutes
20' 10 minutes
10' 5 minutes

As you can see it is very close to what GI wrote. It took me about 30 seconds to come up with it. Even better is that it works very well.

Hope this sheds a little light on things.

SNIP

What Richeod is showing us is an excellent example of what used to be called: "reading the face of the algorithm..." Those of you who studied simple functions or high school calculus might remember all those xy plots to translate basic math functions into a graphical entity.

Anyhow, look at it and try to see what it represents (Rich you're braver than I am to post it!). The 'secret' to begin with is using the right gases but that aside it is being able to look at the pattern that your algorithm kicks out -- any algorithm -- and being able to translate that to the circumstances of the dive... An analogy I use is using standard chord shapes to play barre chords up and down the neck of a guitar... although that might not make sense with out the benefit of a guitar to illustrate my point... OH AUDIO VISUAL AIDS ARE GREAT!!!!

OK... bottom line: What Richeod has given you should answer your questions... However, don't try this at home boys and girls unless you have some mentorship first!

DD

Oh, by the way this technique... was being used long before GUE branded it.

[WreckWriter]

Doppler once bubbled...
(Rich you're braver than I am to post it!).

You guys don't get yourselves in trouble.

You're hinting at the Great and much sought-after Tech 1 secrets here, they might revoke your card for giving this information to mere mortals! :)

You're right, much of this, and other tricks, are not GUE inventions.

WW

[wb416]

WreckWriter once bubbled...


You guys don't get yourselves in trouble.

You're hinting at the Great and much sought-after Tech 1 secrets here, they might revoke your card for giving this information to mere mortals! :)

You're right, much of this, and other tricks, are not GUE inventions.

WW

I don't think Doppler is too concerned about revocation of his Tech 1 card :D

Seriously, on the example given, I would have expected a shape that showed (for example, if using 50/50) a bit more time pulled away from the 60, 50, 40, 30, but the 70 being a bit longer to take advantage of the "O2 Window"...

However, if your example was just to show the ratios, then I digress...

[MikeFerrara]

I'm not sure anyone is really getting my question. In various articles GI gives specific a method for determining the schedule ie...first stop at 80% of max presure with a max time of 5 min scaled based on a bottom time from 0-150 min. From 65% to 45% same scaling with a max time of 10 min. And it goes like that until he gets to 20 ft where he says the 20 ft stop plus the final ascent should at least equal bottom time. And I know he recommends other things like shotening stops before a gas switch ect... However, when I look at the examples he gives it doesn't seem to match up. I am just wondering why.

Other things mentioned like using what we know about the shape to modify or extend a schedule are things we all do there isn't any secret there and for that matter we all develope our own little tricks to streamline the planning process. Again all I'm trying to do is go from GI's directions to the output and connect the two. Also before someone suggests I call or email GI for an explanation, I don't think I'll do that because this is just a point of curiousity for me so I don't care to wast his time over it. I did think, though that someone might know what I was missing off the top of their head.

[O-ring]

From George's post:
Wienke says that at Los Alamos, they can make it come out identical to mine, but I do not know what settings they are using, since obviously I know mine work and don't care what they or anyone else thinks or does, but I doubt that his publicly available program can reproduce what I do.

The trick to doing that is not well understood , but Eric Baker picked right up on it immediately. Ask him. It has to do with how I split the dive into three separate dives and actually am doing three separate decompressions. I don't talk about it much because I only mentioned it in the context of figuring out a ridiculous bottom time extension on the fly, which does not apply to most people because they would have already run out of gas (we are on rebreather for these), and because at the time I did not want anyone to really get it. Now I don't care, since nobody will dare try it anyway.

Andrew has a method for working up an in vitro deco, and that will work just fine. However, if you can follow the logic of mine as well as the logic of all the other tricks, you can throw away your deco program and tables as I did some years ago. The explanation is in one of my articles about a dive that JJ and I did where it ran way over to absurdity, but I can't remember which one it is on the WKPP.org site. Baker will know, he reminded me of it the other day in a conversation we were having.
------------------------------------------------------------------------
This seems like we could figure it out....anybody know Baker pretty well?

[wb416]

Doppler once bubbled...


Hey there CWB (i know who you are!!!)
snip


Egads!! ...and you're willing to admit that!?!

:D bob