deco comparison

[Blackwood]

Let me preface this with: I'm not trimix certified either so this is from a gas planning standpoint only.

I ran the numbers you gave into ideco (.7rmv working and .5rmv deco)
I found that you are pushing your limits with only one bottle unless you are carrying an aluminum 80. If you are carrying an al40 I would consider adding another gas as previous suggested 50% plus 100%
For me I like to have 1.5 times the amount of gas in my deco cylinder. Adding another cylinder helps your odds if you lose your gas that you will have a backup for your deco.

Exactly (the bolded part).

Even if carrying a heiser 190 of 50% I'd add another bottle.

Hypoxic backgas deco from 200 for 20, no thanks.

 

[LiteHedded]

Exactly (the bolded part).

Even if carrying a heiser 190 of 50% I'd add another bottle.

Hypoxic backgas deco from 200 for 20, no thanks.

sissy

 

[Amphiprion]

Let me preface this with: I'm not trimix certified either so this is from a gas planning standpoint only.

I ran the numbers you gave into ideco (.7rmv working and .5rmv deco)
I found that you are pushing your limits with only one bottle unless you are carrying an aluminum 80. If you are carrying an al40 I would consider adding another gas as previous suggested 50% plus 100%, or you could adjust your bottom time. A difference between the two would be about 68 minutes run time with 50% as deco and 59 minutes with 50 and 100.
For me I like to have 1.5 times the amount of gas in my deco cylinder. Adding another cylinder helps your odds if you lose your gas that you will have a backup for your deco.

Totally understand that I would need a lot of gas. My goal was to better understand deco time, depth of stops and gas consumed based on different algorithms using a specific set of parameters. Unfortunately it came out looking like I was asking others to plan my dive for me. This most assuredly was not my intention.

I think what I really want is a graduate level class in decompression physics/chemistry/physiology with algorithm comparison and other inert gasses thrown in for education purposes.

I think the biggest lesson I have learned here is to never post late at night when very sleepy when it reads like I am asking others to plan my dive.

 

[ScubaFeenD]

Totally understand that I would need a lot of gas. My goal was to better understand deco time, depth of stops and gas consumed based on different algorithms using a specific set of parameters. Unfortunately it came out looking like I was asking others to plan my dive for me. This most assuredly was not my intention.

I think what I really want is a graduate level class in decompression physics/chemistry/physiology with algorithm comparison and other inert gasses thrown in for education purposes.

I think the biggest lesson I have learned here is to never post late at night when very sleepy when it reads like I am asking others to plan my dive.

Graduate classes are worthless if you know how to read. The community of decompression research is small and still learning much about the physiology of decompression and decompression models. As a result, you will not get any certainty with regard to deco algorithms or profiles; You will only get the best we have so far.

If you want more after deco for divers I would suggest the rubicon foundation: Rubicon Research Repository: Home

Here you have access to all the primary literature you would want. It's far better than a graduate class, which will just summarize with bias.

 

[M_Bipartitus]

Thanks for the "Deco for Divers" tip. There are so many different algorithms out there for decompression diving, however classes tend to focus on diving skills and number crunching using standard tables. Nobody has taught me a scientifically backed "why" on Buhlmann versus VPM-B versus RGBM, etc. Likewise, I'd love to learn about other inert gasses plugged into these models. Perhaps this is too academic for a standard intro to tech or normoxic class. I was asking for run times from various programs to get a better understanding.

Despite my goofy typo ridden first post, I am actually trained in mandatory decompression, some trimix and advanced nitrox. (Intro to tech with trimix). Started the IANTD normoxic course last week.

As TSandM indicates, you may be disappointed when looking for "scientifically backed" explanations of deco parameters. Most algorithms I'm familiar with takes simple scientific assumptions and use educated guesses or fitting to come up with specific parameters. For example, most algorithms take some number of "tissues" and assume each follows Henry's law for dissolved gasses. This seems perfectly reasonable as a starting point with good scientific evidence behind it (that is Henry's law is well tested with gasses and solutions under pressure). However, very little data exists that directly stipulates what specific parameters should be used for any given gas and tissue compartment. Fortunately there are reasonable guesses that work well when tested, i.e. there are many deco divers who are still alive after using these algorithms.

I would say one of the more scientifically-detailed explanations of deco algorithms would be Technical diving in depth by Bruce Wienke

Amazon.com: Technical Diving in Depth (9780941332972): Bruce R. Wienke: Books

However, I'll warn you that it could be difficult to follow unless you have had something like a college differential equations class, or some upper level college science/engineering classes. I don't think the math is that bad, but he assumes the reader has some familiarity with exponential equations and basic differential equations and/or calculus. If you are really nerdy (like me), you can also search for journal articles by Dr. Wienke. If I recall he is currently using large scale computers to help analyze deco algorithms compared to known dive profiles.

You can also surf through the wealth of information on rubicon-foundation.org. The downside the documents within this site is that they focus on very small parts of the bigger diving picture and it can take a lot of time to figure out what is important to you and what is not.

 

[ScubaFeenD]

I would say one of the more scientifically-detailed explanations of deco algorithms would be Technical diving in depth by Bruce Wienke

Amazon.com: Technical Diving in Depth (9780941332972): Bruce R. Wienke: Books

Thanks for bringing my attention to this. I look forward to reading it.

 

[Garth]

sissy

"no shirt thinks this is funny."

:cool2:

 

[M_Bipartitus]

He has an older book more focussed on Deco, but I'm not sure if it has been updated with as much current information.

Thanks for bringing my attention to this. I look forward to reading it.

 

[ScubaFeenD]

He has an older book more focussed on Deco, but I'm not sure if it has been updated with as much current information.

I assume that you are referring to :Amazon.com: Basic Decompression Theory and Application 3rd Edition (9781930536456): Bruce R. Wienke: Books

 

[M_Bipartitus]

I assume that you are referring to :Amazon.com: Basic Decompression Theory and Application 3rd Edition (9781930536456): Bruce R. Wienke: Books

I guess it has been updated. I suspect that this is more detailed than the previously mentioned book as "Technical Diving in Depth" covers additional topics in about the same length.