often in those calm conditions you have haze and restricted visibility. If a destroyer is comming at you and is about 2000 meters away. If you crash dive, you should have about 40 meters depth when he is on top of you. Ikeep flank speed until I have 20-25 meters abobe me. then go silent to 2 kts, rudder 10 degres either port or starboard. When the DD makes its first pass I go flank until the wasserbomben explode & go quiet again. Hope this helps in the future.
