Pulp Krieg: Decompression Rules
$Revision: 1.4 $

Decompression Tables

Here is a brief rundown of how much time you need to wait at each depth to avoid decompression sickness. Before we go on with the explanation let me add a little disclaimer:
The following data are just a pure abstraction for game purposes. Do not use it for any real-life situation!

In the following table you will find data for different depths (up to 60 meters) and different time periods (from 15 minutes to 3 hours). In order to define how much a character needs to wait in order to complete decompression, first find out the max depth to where he arrives during his dive. Then find out how much time he spends at the given depth (round at the nearest quarter of hour).
After having selected the duration subtable and the depth row, move to the left of one row and you will find how long a character has to wait at the corresponding depth before going up. The procedure is repeated for each depth "band".

Let's say, as an example, that your PC reaches a depth of 42 meters and remains there for 25 minutes. You should consult the subtable for 30 minutes and check the numbers for a stay at 40 meters.
The actual procedure to decompress is to move "up" towards the surface and wait there for a given number of minutes. In our example, the diver should move to the 30 meters zone and wait 21 minutes.
After having completed this phase, he will move up to the 20 meters zone and wait the indicated time (26). After that, he will reach the 10 meters zone, and after another 31 minutes he will be free to resurface.
Note that the total time required before resurfacing is 21+26+31=78 minutes. A character is not required to remain motionless during the decompression waiting phases, so if he has anything useful to do at different depths he can plan accordingly and carry out some other tasks while waiting.

00:15
10 m.20 m.30 m.40 m.50 m.60 m.
201815116 - 
141295
974
53
2
00:30
10 m.20 m.30 m.40 m.50 m.60 m.
31262114 7 - 
2419147
17127
105
5
00:45
44352617 8 - 
3627189
27189
189
9
01:00
60453219 9 - 
51362310
412613
2813
15
01:15
795738229 - 
70482913
573516
4119
22
 01:30
10371452410 - 
93613514
794721
5826
32
01:45
13286522710 - 
122764217
1055925
8024
56
 02:00
166104602910 - 
156945019
1377531
10644
62
02:15
206124683211 - 
1951135721
1749236
13856
82
 02:30
253147773511 - 
2421366624
21811242
17670
106
02:45
308173873711 - 
2971627626
27113650
22186
135
 03:00
371201984011 - 
3311615829
30213229
273103
170

Decompression sickness

Modeling decompression problems is quite complex, too. As a rule of thumb, if a character is somewhat forced to resurface without proper decompression procedure, he will have to make a number of Health rolls threshold for each 30 minutes (or fractions) interval spent below 10 meters (minimum 1). The difficulty for these rolls is equal to 1 plus the maximum depth he reached, in meters, divided by 10. So if he remained 2 hours at 40 meters and could not complete the decompression procedure, he will have to make 4 rolls on Health against 5. For each failed roll, apply a damage of 10 x margin of failure.
Another factor which is usually downplayed in fiction is that repetitive diving has a cumulative effect on the risks of decompression. The "safe" rule is to avoid diving more than once a day. If someone is forced to get underwater more than once in a 12 hours time span, add half the depth and duration of the previous dives to the current one when trying to determine the effects.
So, for example, if the PC dived to 40 meters for 30 minutes at noon, when adjudicating decompression problems for another identical dive done later in the same day, count it as a 45 minutes immersion at 60 meters.