I'm researching for a book I am writing (Fiction) set from 1935 - 48 in Kiel, but it involves a voyage from Kiel to the East coast of the UK. I am struggling to find details about coastal defenses on the Baltic sea and the north sea, specifically Germany and Denmark, including minefields in both sea areas. In the Baltic, the Skagerrak and the Heligoland Bight. I also need to find out in a bit more detail about minefields in and on the approaches to Kiel Hafen, and if there was a marine barrier at the entrance. Allied minefields on the east coast of the UK would be useful too, but that's for another forum!