WAGNER: In the middle of the map you will find the British Isles. The large part of the ocean which is shaded on the edge shows the afore-mentioned American combat zone. The shaded parts of the sea near the British coast are those parts which were ordered to be German submarine operational zones. They were given letters from A to F in accordance with the time when they were set up.
FLOTTENRICHTER KRANZBÜHLER: Can you tell us up to which depth these German operational zones went?
WAGNER: I think perhaps as far as the 200 meter line.
FLOTTENRICHTER KRANZBÜHLER: Does this depth guarantee favorable use of mines?
WAGNER: Yes, down to 200 meters the use of anchored mines is possible without any difficulty.
FLOTTENRICHTER KRANZBÜHLER: In these operational zones certain dates have been entered. Will you please explain how it happened that on those particular dates, and in that sequence, these territories were made operational zones?
WAGNER: All those areas were declared to be operational zones where our fighting forces came into contact with enemy traffic and a concentration of the enemy defense, resulting in main combat areas.
To begin with, they were the zones at the northern and southern end of the German-mined zones which had been declared along the British East Coast and in the Bristol Channel. You can see, therefore, that Zone A lies to the east of Scotland and is dated 6 January. The Bristol Channel Zone is dated 12 January, and finally at the southern end of this danger zone, that is, to the east of London, there is the date of 24 January.
Later on, according to the fluctuations of the actual fighting, further areas around the British Isles and then off the French Coast were designated.
FLOTTENRICHTER KRANZBÜHLER: Up to what date did this development continue?