scubabunny
Guest
What to you is a proper comuter?
Decompression Thoughts
- Thread starter jimbo
- 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
Jimbo origionally refered to upgrading to 'a nitrox/air cadillac model'. Rather than repeat this I just called it a propper computer.
For my *personal* use, a computer that
1) does nitrox
2) Can cope with 2 mixes (minimum) on a dive
3) Doesn't throw 'heeby jeebies' when I do a propper planned deco dive
4) Allows me some reasonable choice over settings, AND COMES WITH GOOD EXPLANATIONS as to WHAT you are changing and how it affects the algorithm
5) Is non air-integrated
6) Can be moved from air - nitrox mode (or change mode) during a surface interval - a lot don't let you change modes untill you are completely unsaturated (or will only let you dive nitrox of an equal or higher % mix)
7) Has a Display that I like
8) User changeable batteries
9) Has the algorithm in the public domain, and all the 'proprietory changes' to the algorithm in the public domain also.
The list goes on..... but that is what for my diving is a 'propper' computer.
Jon T
PS My prefered tables are the buehlmann, as that has a well defined algorithm from actual experiments. The PADI tables are 2nd favourite, The maths behind them is clouded in secrecy, but they have the edge in that Dr Deco did real human trials on them.
For my *personal* use, a computer that
1) does nitrox
2) Can cope with 2 mixes (minimum) on a dive
3) Doesn't throw 'heeby jeebies' when I do a propper planned deco dive
4) Allows me some reasonable choice over settings, AND COMES WITH GOOD EXPLANATIONS as to WHAT you are changing and how it affects the algorithm
5) Is non air-integrated
6) Can be moved from air - nitrox mode (or change mode) during a surface interval - a lot don't let you change modes untill you are completely unsaturated (or will only let you dive nitrox of an equal or higher % mix)
7) Has a Display that I like
8) User changeable batteries
9) Has the algorithm in the public domain, and all the 'proprietory changes' to the algorithm in the public domain also.
The list goes on..... but that is what for my diving is a 'propper' computer.
Jon T
PS My prefered tables are the buehlmann, as that has a well defined algorithm from actual experiments. The PADI tables are 2nd favourite, The maths behind them is clouded in secrecy, but they have the edge in that Dr Deco did real human trials on them.
Jon,
Abyss has an article (Understanding M Values by Eric Baker) that gives the M values for a variety of deco algorithms. Included in this is the values from DSAT for the RDP. No guarantee that the figures are correct.
Taking the naive approach of instantaneously arriving at depth and not allowing for gas loading/unloading on ascent, it is possible to calculate the theoretical NDLs for the DSAT values. The values are:
Depth MSW Theoretical RDP
10.5 258.76 219
12 161.30 147
14 107.06 98
16 78.12 72
18 59.26 56
20 48.40 45
22 39.15 37
25 30.74 29
30 19.66 20
35 14.71 14
40 10.96 9
42 9.98 8
Seems that calcs are close(ish) to the table value.
Thought you might be interested.
DiverDave
Abyss has an article (Understanding M Values by Eric Baker) that gives the M values for a variety of deco algorithms. Included in this is the values from DSAT for the RDP. No guarantee that the figures are correct.
Taking the naive approach of instantaneously arriving at depth and not allowing for gas loading/unloading on ascent, it is possible to calculate the theoretical NDLs for the DSAT values. The values are:
Depth MSW Theoretical RDP
10.5 258.76 219
12 161.30 147
14 107.06 98
16 78.12 72
18 59.26 56
20 48.40 45
22 39.15 37
25 30.74 29
30 19.66 20
35 14.71 14
40 10.96 9
42 9.98 8
Seems that calcs are close(ish) to the table value.
Thought you might be interested.
DiverDave
HTML has decided to eliminate all my spaces in the table 
First numbers are depth in metres
Second set (2dec places) is the theoretical NDL
Last set is the RDP numbers.
First numbers are depth in metres
Second set (2dec places) is the theoretical NDL
Last set is the RDP numbers.
Don't know if this one is dead yet but one of the things jmbo mentioned was cold water.
Make sure your computer of choice takes into account water temperature in it's algorithm would be my recommendation. I know the uwatec ones do and they have various models so there should be one to suite your diving.
Also Nitrox becoming more and more popular you may want to look at one that can handle that. Or you could always use Nitrox and dive air profiles for added conservatism.
Jonathan
Make sure your computer of choice takes into account water temperature in it's algorithm would be my recommendation. I know the uwatec ones do and they have various models so there should be one to suite your diving.
Also Nitrox becoming more and more popular you may want to look at one that can handle that. Or you could always use Nitrox and dive air profiles for added conservatism.
Jonathan
Similar threads
