Now you have decided on the best course of action, perhaps you would like to remove the % hit in using your choice.
Open up GamePlaySettings.cfg and scroll to the bottom to see this:
[RealismPercentage]
LimitedBatteriesRealismPercentage=5
LimitedCompressedAirRealismPercentage=1
LimitedO2RealismPercentage=12
LimitedFuelRealismPercentage=6
RealisticVulnerabilityRealismPercentage=5
RealisticRepairTimeRealismPercentage=8
RealisticShipSinkingTimeRealismPercentage=2
ManualTargetingSystemRealismPercentage=0
NoMapUpdateRealismPercentage=11
RealisticSensorsRealismPercentage=10
DudTorpedoesRealismPercentage=5
RealisticReloadRealismPercentage=10
NoEventCameraRealismPercentage=3
NoExternalViewRealismPercentage=0
NoStabilizeViewRealismPercentage=10
NoNoiseMeterRealismPercentage=12
NoWeaponOfficerAssistRealismPercentage=0
You can change any of these % figures to suit your needs, just as long as all the lines add up to 100 after your changes.
I edit mine so that I am forced to 100% and can't 'teleport back to base.
P.S The usual blurb about modding while at sea etc.........