I have a success sinking ships in bad weather without any visual contact, just by my sonar man and four bearings method (without the 5th) while on the move. Then I set course to intercept for gyro 0 shot, and adjust the final range by active sonar... Oh and I'm not using position keeper in this case.
In addition I want to say, when it's raining, DD's should struggle trying to find you because they will not be able to hear your engines.
So just start moving...
Good luck!
