make-deco-table demonstration

Uwe Ohse / available software / The mosquitotools package / mosquitotools demo main page

make-deco-table demonstration

This page demonstrates a few things make-deco-table can do for you. While the rest of this page is nothing more than a blatant ad for the program, i feel it's fair to inform you that it has a few limitations, too.

Creating a decompression table for 40meter and up to 60 minutes

command: make-deco-table 40 60

output:

Decompression table for 40 meter depth and a nitrox percentage of 78.0%.
Decompression model used: zhl16b

Assumptions:
* Maximum descend speed: 20.0 meter/minute
* Maximum ascend speed: 10.0 meter/minute

Ground   3m   6m   9m  12m  15m  20m total
-time
    8     1                              1
    9     2                              2
[...]
   59    83   42   24   16    8    5   178
   60    85   43   25   16    8    5   182

I'll leave the header out in future examples, unless there's something interesting in it.

Creating a smaller decompression table for 40 meters and up to 60 minutes

command: make-deco-table 40 60 0 5 "Create a decompression table for 40 meters and 60 minutes, starting from 0 and using ground time intervals of 5 minutes"

output:

Ground   3m   6m   9m  12m  15m  20m total
-time
   10     2                              2
   15     7    3                        10
   20     9    6    3                   18
   25    18    8    5    1              32
   30    25   11    7    4              47
   35    31   17    8    6    1         63
   40    42   21   10    7    4         84
   45    48   26   15    8    6        103
   50    57   30   19   10    6    2   124
   55    71   37   21   14    7    3   153
   60    85   43   25   16    8    5   182

Same depth, same ground times, EAN32

command: make-deco-table --nitrox-fraction 0.68 40 60 0 5 "Create a decompression table for 40 meters and 60 minutes, starting from 0 and using ground time intervals of 5 minutes, using a nitrox fraction in the breathing gas of 32%"

output:

Decompression table for 40 meter depth and a nitrox percentage of 68.0%.
Decompression model used: zhl16b

Assumptions:
* Maximum descend speed: 20.0 meter/minute
* Maximum ascend speed: 10.0 meter/minute
*** The generated table must not be used: Oxygen partial pressure to high, over 1.4 bar


Ground   3m   6m   9m  12m  15m total
-time
   15     3                         3
   20     6    2                    8
   25     8    5    1              14
   30    13    7    2              22
   35    16    8    5              29
   40    21   11    6    1         39
   45    24   14    7    3         48
   50    30   16    8    5         59
   55    35   18   11    6         70
   60    38   21   13    7    1    80

This isn't the safest mix to use at this depth, as the warning says.

Same depth, same ground times, Air, using higher safety margins

By default make-deco-table assumes that the nitrogen load of the tissues shall stay below 0.737 of the maximum allowed. This default creates tables which a safety margin being at the level of the deco2000 table or safer. It's possible to generate even safer tables:

command: make-deco-table --load-margin 0.66 40 60 0 5 "Create a decompression table for 40 meters and 60 minutes, starting from 0 and using ground time intervals of 5 minutes, with load spikes staying below 0.66 bar."

output:

Decompression table for 40 meter depth and a nitrox percentage of 78.0%.
Decompression model used: zhl16b

Assumptions:
* Maximum descend speed: 20.0 meter/minute
* Maximum ascend speed: 10.0 meter/minute
* Tissue load safety margin: 0.66 (safer)

Ground   3m   6m   9m  12m  15m  20m  25m total
-time
   10     4    1                              5
   15     9    4    2                        15
   20    16    8    4    2                   30
   25    25   11    8    4    1              49
   30    34   19    9    7    3              72
   35    47   25   14    8    6    1        101
   40    59   31   20   10    7    4        131
   45    78   41   23   15    7    7        171
   50    98   49   29   19   10    7    2   214
   55   125   56   34   21   14    7    4   261
   60   149   67   41   26   17    9    6   315

Additional safety has a price...

Same depth, same ground times, Air, highest deco stop on 6 meters

Sometimes it's a good idea to leave the 3 meter decompression depth out. This may be due to waves or the fact, that there's absolutely nothing to see at 3 meters...
It's unsafe to simply add the time at 3meters to the 6 meter decompression step, as the time needed to desaturate a tissue depends on the difference between the tissues nitrogen partial pressure and the nitrogen partial pressure of the air one breaths. To keep the same safety margins as ever one has to use special decompression tables in that case.

Let's say we want out last decompression step to be on 6 meters:

command: make-deco-table --deco-steps 6,9,12,15,18,21 40 60 0 5 "Create a decompression table for 40 meters and 60 minutes, starting from 0 and using ground time intervals of 5 minutes, with possible decompression steps step at 6, 9, 12, 15, 18 and 21 meters."

output:

Ground   6m   9m  12m  15m  20m total
-time
   10     3                         3
   15    12                        12
   20    20    3                   23
   25    35    5    1              41
   30    53    7    4              64
   35    76    8    6    1         91
   40    98   10    7    4        119
   45   120   15    8    6        149
   50   165   19   10    6    2   202
   55   210   21   14    7    3   255
   60   279   25   16    8    5   333

Additional comfort has a price, too.

The --deco-steps option may be used to create a number of stranger decompression rules - one may, for example, create a rule with decompression steps at 3, 9 and 12 meters:

command: make-deco-table --deco-steps 3,9,12 40 60 0 5

output:

Ground   3m   9m  12m total
-time
   10     2               2
   15     7    4         11
   20    10   10         20
   25    19   16    1    36
   30    27   23    4    54

Showing a decompression rule graphically

The --profile option causes to print out a single decompression rule as a dive profile.

command: make-deco-table --profile 40 30 \ mosquitograph --load-ambient-% - |groffer -pt "Create a decompression rule for 40 meters and 30 minutes, starting from 0 and using ground time intervals of 5 minutes, with the last decompression step being 6 meters.": output: shown in an X window on your screen.

Using feet instead of meters

command: make-deco-table --feet 100 60 0 5 "Create a decompression table for 100 feet and 60 minutes, starting from 0 and using ground time intervals of 5 minutes."

output:

Decompression table for 100 feet depth and a nitrox percentage of 78.0%.
Decompression model used: zhl16b

Assumptions:
* Maximum descend speed: 65.6 feet /minute
* Air pressure about: 1000.0 mbar
* Maximum ascend speed: 32.8 feet/minute

Ground  10f  20f  30f  40f total
-time
   15     2                    2
   20     6                    6
   25     9    3              12
   30    12    7              19
   35    18    8    2         28
   40    22   10    5         37
   45    28   13    7         48
   50    31   17    9         57
   55    39   20    9    3    71
   60    45   23   12    4    84

The --feet option may be combined with the --deco-steps option:

command: make-deco-table --feet --deco-steps 7,15,22,30 100 60 0 5 "Create a decompression table for 100 feet and 60 minutes, starting from 0 and using ground time intervals of 5 minute, doing decompression on 7, 15, 22 and 30 feet."

output:

Ground   7f  15f  22f  30f total
-time
   15     2                    2
   20     4    2               6
   25     5    6              11
   30     8    6    4         18
   35    13    6    7         26
   40    15   10    5    5    35
   45    18   12    7    7    44
   50    21   14    9    9    53

Additional information

make-deco-table has a number of options to influence table generation. They include higher or lower ascend speeds, air surface PRessure (for dive tables to be used in the mountains), using faster or slower saturation and desaturations times and options to create different output formats.
These options are described in make-deco-table (1).