[tedhealy]

edited for updates/changes

I've been trying to come up with a system to simulate random breakdowns that would force you to return to base(RTB). Inspired by the terrific solitaire boardgame Silent War, I thought I'd share what I've come up with and ask for suggestions on changes or additions. I have yet to do a career/patrol with this system as this is just preliminary stuff I came up with. I'll start trying it out next patrol.

All you need is a 6 sided die (d6) and a small scrap of paper to note some rolls/results. It takes much longer to explain than it should to actually do in game.

Basically you do a check once a week, every week (it does not have to be done on the same day each week, just as long as it is done once in a 7 day period) to see if you have to RTB due to malfunction/breakdown. I want a RTB result to be rare, but not so rare that you never see it in a career. Plus the longer you are out at sea, the higher the risk of RTB.

I came up with 2 options, a simple one that just checks if you have to RTB and a more complex one that simulates damage/repair and possible RTB based on that damage.

Option 1 - Simple

Make a RTB Roll Check once a week for entire patrol. You may make the roll at anytime in that 7 day period. Ex: You could roll every Tuesday night, or you could roll on the 7th day your first week, and on the 1st day your 2nd week, or however you decide. You might want to vary when you roll based on the situation you are in, but you must make a roll every week.

If the roll results in 7 or greater (after any modifiers listed below), then roll again for Possible RTB to see if you have to RTB.

RTB Roll Check

Roll d6 and add the applicable die roll modifiers (drm)

drm
+1 S-Boat
+1 50-75% fuel remain
+3 25-50% fuel reamin
+5 < 25% fuel remain
+1 <= 50% torpedoes left

On a result 7 or greater, roll for Possible RTB. If less than 6, do not roll Possible RTB.

Possible RTB Roll

Roll d6.

drm
+1 for every possible RTB roll made previously in patrol (cumulative)
+1 S-Boat
+1 50-75% fuel remain
+3 25-50% fuel reamin
+5 < 25% fuel remain
+1 <= 50% torpedoes left

on a modified result of 8 or greater, RTB immediately due to an unfixable breakdown, supply situation, or other reason.

Any result less than 8 does not result in a serious enough problem to be forced to RTB, but note that it will modify your next Possible RTB roll by +1 and it is cumulative.

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

Option 2 - rpg style

Make a RTB Roll Check once a week for entire patrol. You may make the roll at anytime in that 7 day period. Ex: You could roll every Tuesday night, or you could roll on the 7th day your first week, and on the 1st day your 2nd week. You might want to vary when you roll based on the situation you are in, but you must make a roll every week.

RTB Roll Check

Roll d6 and add the applicable drm

drm
+1 S-Boat
+1 50-75% fuel remain
+3 25-50% fuel reamin
+5 < 25% fuel remain

On a result of 6 or greater, continue on and make a Damage Area roll and Damage Seriousness roll. On a result less than 6, you are done for the week.

DAMAGE AREA
On a 6+ RTB Roll Check, roll d6 and check for area below

Before Mid 1943
1 - Batteries
2-3 - Radar/Electrical (if no SJ radar, treat as Engines result)
4-5 - Torpedoes
6 - Engines

After Mid 1943
1 - Batteries
2-4 - Radar/Electrical (if no SJ radar, treat as Engines result)
5 - Torpedoes
6 - Engines

DAMAGE SERIOUSNESS
Roll d6 for seriousness, add apllicable drm, and check area table for result.

drm
+3 if identical area has broken down before in patrol (not cumulative)

Results Overview (see specific area table for specific result)

1-5 - Little to minor damage. Fixed in under an hour - In the time it took to explain the problem to the captain, the problem was taken care of.
6 - Moderate damage discovered. It will take approximately 6 hours to repair.
7 - Serious damage discovered. It will take approximately 18 hours to repair.
8 - Very serious damage discovered. It will require cannibalizing parts and days of testing and re-testing and even then it may not get fixed.
9 - Unfixable at sea.

RESULT TABLES

Batteries
1-5 - Last battery check produced unexpected results but upon further inspection, levels look normal.
6 - Cannot go faster than standard when submerged. Can submerge to repair for full 6 hours if wanted. Problem fixed in 6 hours.
7 - Can submerge for up to 6 hours during 18 hour repair time (some time is needed not using batteries to fix them), cannot go faster than 2/3 when submerged. Officers divided on whether or not this is serious enough to force RTB.
8 - RTB suggested by XO, this is a serious issue and not 100% fixable at sea. Can submerge for 1 hour per day for remainder of patrol. Cannot go faster than 2/3 when submerged. Treat further battery results as no effect.
9 - XO and other officers suggest RTB immediately, this is a serious and dangerous issue with the batteries. Cannot go faster than 1/3 when submerged and cannot recharge the battery (turn off battery recharge in command menu immediately upon surfacing every time). Treat further battery results as no effect.

Radar/Electrical
1-5 - No effect, must be gremlins in the system.
6 - Radar unusable in anything but shortest range for 6 hours during repair.
7 - Radar unusable for 18 hours during repair.
8 - Radar unusable until next RTB Roll Check. With limited spare parts, long hours and days, and some outside the box thinking, it can be fixed. Officers divided about RTB issue as the radar seems faulty.
9 - Radar unusable for rest of patrol, XO suggests RTB, but not all officers agree. Treat further Radar/Electrical results as no effect.

Torpedoes
1-6 - No effect, reports from other captains about and your own experience with faulty torpedoes have you on edge over their quality. You have the crew examine the fish (again).
7 - Problem with torpedoes discovered, every single one needs to be checked and rechecked and many worked on before firing them would be considered safe, no firing for 18 hours.
8 - Problem with torpedo tubes/doors, no firing until next RTB Roll Check. The problem is serious and may require someone to go over the side to inspect the outside doors, but the problem is fixable. It will just require time. Officers divided on RTB issue.
9 - Unfixable torpedo problem, torpedo doors will not open, XO and officers suggest immediate RTB unless on spy/supply mission. Treat further Torpedoes result as no effect.

Engines
1-5 - No effect, engines didn't sound right, but appear to be working within tolerance.
6 - A diesel engine has to be shut down for repair. Reduced speed on surface, cannot exceed standard speed on surface for next 6 hours during repair.
7 - Reduced speed, cannot exceed 2/3 speed on surface for next 18 hours during repair, also cannot recharge batteries for 18 hours (turn off recharge in command menu). Officers divided on RTB.
8 - Engines likely to break down soon, something is seriously wrong. XO suggests RTB. IF RTB, cannot exceed standard speed on surface. If continuing patrol, cannot exceed 2/3 speed on surface. Treat further Engines result as no effect
9 - At least one diesel will not work, XO and other officers suggest RTB immediately, do not exceed 2/3 speed on surface. Treat further Engines result as no effect