Such actions as that on November 17, 1917, between our light forces and the German light cruisers and minesweepers were the result.

We did not, of course, lay mines in either the Danish or Dutch territorial waters, and these waters consequently afforded an exit for German vessels as our minefields became most distant from German bases.
Broadly speaking, the policy was to lay mines so thoroughly in the Heligoland Bight as to force enemy submarines and other vessels to make their exits along the Danish or Dutch coasts in territorial waters.
At the end of the exit we stationed submarines to signal enemy movements and to attack enemy vessels.

We knew, of course, that the enemy would sweep other channels for his ships, but as soon as we discovered the position of these channels, which was not a very difficult matter, more mines were laid at the end.

In order to give neutrals fair warning, certain areas which included the Heligoland Bight were proclaimed dangerous.

In this respect German and British methods may be contrasted: We never laid a minefield which could possibly have been dangerous to neutrals without issuing a warning stating that a certain area (which included the minefield) was dangerous.