[Beery]

I think flak gun compartments have to be at least at half-full efficiency in order to work. For the boats with 4 flak guns it's harder to get the efficiency high enough when you have a fully fatigued crew. You may need to get at least a couple of NCOs trained up on the flak guns in order to get them to work while the crews are fully fatigued (an officer may not be enough). Alternatively, keep your flak gunners fully rested until you need them. There's no point in manning every compartment all the time, so it should be possible to keep some essential personnel rested for months.