The weather outside Brest was foggy with rain. The moment Brest was taken by German forces, I entered the straits. Out of the gloom a destroyer appeared. It was British and it had a friend behind him. We passed each other not three hundred meters appart. I ordered a normal dive. We were at 17 meters when both destroyers returned pinging. They dropped a bunch of charges for about an hour, then left.
A good idea when entering a newly occupied port, is to give time for enemy vessels to leave.