deco software
- Thread starter doc6464
- Start date
Please register or login
Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.
Benefits of registering include
- Ability to post and comment on topics and discussions.
- A Free photo gallery to share your dive photos with the world.
- You can make this box go away
Doc, wait till Mario and the others get back from DEMA this week. There'll be reports on all the cool new stuff!
Doc,
Yes Deco Planner available from GUE is very easy to use. It uses a 16 compartment Bühlmann algorithm with deep stops and helium. If you buy it you also will be signed up to an e-mail list where you can search the archives about past questions and also ask questions directly to the guys who programmed it.
If you want to see how this type of deco program works you can get GAP for free at:
http://www.gap-software.com/
GAP is a fully-fledged decompression program that utilises unpadded bulhmann's decompression algorithm for mixed gas decompression. As an add-on it is also supplied with the deep stop algorithm developed by Erik Baker which is also used by decoplanner.
The main difference is that it has a Graphical Interface opposed to the a lot of other decompression programs with include the deep stop algorithm devised by Erik Baker
When the deep stop settings are off, GAP gives you the straight unpadded Bühlmann algorithm. This has been thoroughly tested in the normal diving range (0-50 metres) but may be too liberal for some people.
Brad
Yes Deco Planner available from GUE is very easy to use. It uses a 16 compartment Bühlmann algorithm with deep stops and helium. If you buy it you also will be signed up to an e-mail list where you can search the archives about past questions and also ask questions directly to the guys who programmed it.
If you want to see how this type of deco program works you can get GAP for free at:
http://www.gap-software.com/
GAP is a fully-fledged decompression program that utilises unpadded bulhmann's decompression algorithm for mixed gas decompression. As an add-on it is also supplied with the deep stop algorithm developed by Erik Baker which is also used by decoplanner.
The main difference is that it has a Graphical Interface opposed to the a lot of other decompression programs with include the deep stop algorithm devised by Erik Baker
When the deep stop settings are off, GAP gives you the straight unpadded Bühlmann algorithm. This has been thoroughly tested in the normal diving range (0-50 metres) but may be too liberal for some people.
Brad
Dr Deco
Contributor
- Messages
- 2,384
- Reaction score
- 96
- # of dives
- I just don't log dives
Doc 6464:
I cannot personally give you any information on these decompression methodologies. With the exception of Prof. Buhlmann's work, as I have never seen any test data describing how the models were developed and parameterized. These are mostly black boxes. :all:
I cannot personally give you any information on these decompression methodologies. With the exception of Prof. Buhlmann's work, as I have never seen any test data describing how the models were developed and parameterized. These are mostly black boxes. :all:
I am curious and for my own benefit
.
1.) Does this mean that you consider any decompression algorithm a black box if you have not seen the data population used to determine the distribution and subsequent parameters used in the implementation of the gas loading estimations?
2.) What commercially available decompression software and/or computer(s) have you had the opportunity to review and what are your opinions of it?
Brad
1.) Does this mean that you consider any decompression algorithm a black box if you have not seen the data population used to determine the distribution and subsequent parameters used in the implementation of the gas loading estimations?
2.) What commercially available decompression software and/or computer(s) have you had the opportunity to review and what are your opinions of it?
Brad
Dr Deco
Contributor
- Messages
- 2,384
- Reaction score
- 96
- # of dives
- I just don't log dives
Dear Atomox:
1. Algorithms
If one looks at the decompression profiles of the various tables and decompression computers, you will note that there are not large differences between them. Some computers even have several algorithms and allow you to make a choice. It is clear to me that there are many pathways from depth to surface and that they all have a certain degree of merit.
When I say that I have not seen the parameters used to construct the algorithm, I am also including the fact that many or these have not been tested in the laboratory, although all are derived from field data and thus have some basis in fact. It would be interesting to see side-by-side comparisons of these algorithms in controlled, laboratory trials with Doppler ultrasound bubble detection data. These are very expensive however, and I doubt that these will be forthcoming. Therefore, we have many tables based on personal theory and little lab data to support it. This is not meant to imply that the tables or deco meters are not good, only that I am not sure that they work for the reasons given by the manufacturer.
An example would be that many of the deep profile meters are all for in-water decompression. We know from our work at NASA that when individuals are not standing on the legs, this work is absent and micronuclei formation is decreased. This is important in astronauts who only float in space, but it also applies to scuba dives since they are floating in water. When comparisons are made to decompressions from traditional tables (such as the US Navy), it should be remembered that these are conducted in a dry chamber since the navy and commercial groups no long perform in-water decompression. Thus, when a comparison is made of the efficacy of a new table versus the in-chamber decompression (when the individuals always have the opportunity to stand and walk around and are encouraged to do so), we must remember that one group is adynamic (in water) and one group is generating micronuclei (chamber and exposed to 1-g forces).
It is not possible to tell exactly what is occurring with respect to these decompressions unless both procedures were conducted in the water and/or in a chamber. That is the comparison as far as nuclei concentration in the tissues is concerned. Thus, the underlying theory may or may not be correct, but it cannot be determined directly from the in-water decompressions.
Tables and procedures with deep stops are very good on a theoretical basis, but I do not know if the procedures are optimal, since I do not know the conditions under which the tables were developed. I have known many table designers in my years in the barophysiology business, and all believed very strongly in their underlying theories. Most tables worked but not for the reasons given; they worked because of the underlying data used to generate them.
In addition, we know that not all individuals share the same sensitivity to decompression. Some people are more resistant. I do not know that the divers used to parameterize these deep procedures are not more resistant to DCS. I can certainly imagine that if a rec diver were sensitive to DCS, he or she would not progress on to performing long decompressions from bottom depths of 300 to 400 feet. The element of randomization is therefore missing in the test population.
2. Tables
I have not actually reviewed any of these devices since NASA does not perform deep dives. I have little first hand knowledge.
Certainly, the procedures of Prof. Buhlmann are well documented and represent a tested methodology. The DSAT Recreational Dive Planner is a straightforward procedure that has also be described in its development and testing, but this is not for deep diving.
In all of these systems, you always have the option of safety stops, decreasing the bottom time, and increasing the surface interval. The following have been mentioned before and are included again in this FORUM. They are not a part of any deco computer or table.
1. Algorithms
If one looks at the decompression profiles of the various tables and decompression computers, you will note that there are not large differences between them. Some computers even have several algorithms and allow you to make a choice. It is clear to me that there are many pathways from depth to surface and that they all have a certain degree of merit.
When I say that I have not seen the parameters used to construct the algorithm, I am also including the fact that many or these have not been tested in the laboratory, although all are derived from field data and thus have some basis in fact. It would be interesting to see side-by-side comparisons of these algorithms in controlled, laboratory trials with Doppler ultrasound bubble detection data. These are very expensive however, and I doubt that these will be forthcoming. Therefore, we have many tables based on personal theory and little lab data to support it. This is not meant to imply that the tables or deco meters are not good, only that I am not sure that they work for the reasons given by the manufacturer.
An example would be that many of the deep profile meters are all for in-water decompression. We know from our work at NASA that when individuals are not standing on the legs, this work is absent and micronuclei formation is decreased. This is important in astronauts who only float in space, but it also applies to scuba dives since they are floating in water. When comparisons are made to decompressions from traditional tables (such as the US Navy), it should be remembered that these are conducted in a dry chamber since the navy and commercial groups no long perform in-water decompression. Thus, when a comparison is made of the efficacy of a new table versus the in-chamber decompression (when the individuals always have the opportunity to stand and walk around and are encouraged to do so), we must remember that one group is adynamic (in water) and one group is generating micronuclei (chamber and exposed to 1-g forces).
It is not possible to tell exactly what is occurring with respect to these decompressions unless both procedures were conducted in the water and/or in a chamber. That is the comparison as far as nuclei concentration in the tissues is concerned. Thus, the underlying theory may or may not be correct, but it cannot be determined directly from the in-water decompressions.
Tables and procedures with deep stops are very good on a theoretical basis, but I do not know if the procedures are optimal, since I do not know the conditions under which the tables were developed. I have known many table designers in my years in the barophysiology business, and all believed very strongly in their underlying theories. Most tables worked but not for the reasons given; they worked because of the underlying data used to generate them.
In addition, we know that not all individuals share the same sensitivity to decompression. Some people are more resistant. I do not know that the divers used to parameterize these deep procedures are not more resistant to DCS. I can certainly imagine that if a rec diver were sensitive to DCS, he or she would not progress on to performing long decompressions from bottom depths of 300 to 400 feet. The element of randomization is therefore missing in the test population.
2. Tables
I have not actually reviewed any of these devices since NASA does not perform deep dives. I have little first hand knowledge.
Certainly, the procedures of Prof. Buhlmann are well documented and represent a tested methodology. The DSAT Recreational Dive Planner is a straightforward procedure that has also be described in its development and testing, but this is not for deep diving.
In all of these systems, you always have the option of safety stops, decreasing the bottom time, and increasing the surface interval. The following have been mentioned before and are included again in this FORUM. They are not a part of any deco computer or table.
- take a safety stop, and move your arms and legs at the stop to promote the flow of blood;
- avoid those straining activities that promote the formation and growth of micronuclei in tissues (e.g., climbing ladders will full gear, and lifting heavy tanks and weight belts)
- avoid remaining sedentary during the surface intervals(do not sleep) but rather remain seated but move arms and legs to promote the flow of blood.
- avoid physically strenuous activities during the surface interval and following the dive, do not run (strenuous), for example, for several hours post surfacing.
- remember to stay well hydrated as this promotes perfusion (= blood flow) and increases the surface tension of the bodies fluid to as high a value as possible.
Good luck
___________________________
[sp] Dr Deco
Doc, Great question... hehe I was actually writing up a little something on the topic. I personally use Abysmal's software for Deco planning. Many professionals use the software because of the amount of bells & whistles and therefore advantages it offers. It will even allow you to plan complex multi mix extended range dives. I have some contacts at the company... more on that later!
Similar threads
