Abstract :
EARLY in World War II the German Navy and Air1 Force started to lay a new type of sea mine, reputed later to be the first of the “secret weapons.” This mine was detonated at a distance beneath a ship by the ship´s influence rather than by actual contact as was necessary for previous types of mines. Due to the mystery surrounding the means of operation of this mine and the lack of countermeasures, it was a threatening weapon to Allied shipping.
