The italian Frogmen
Pursuant to Italy's declaration of war on Austria, Austria quickly invaded practically all of northern Italy, its armies rolling southward with impunity. Having soundly defeated the Italians at the battles of Caporetto and Longarone. the Austrian forces pushed southward. On reaching the Piave River, their attacks were blunted by a resolute Italian army whose soldiers miraculously held back a superior Austrian force at the cost of turning the River red weh blood. At the same time, Austria's overpowering navy, which relentlessly bombarded Italy's cities at will, was about to be challenged by a small group of Italian frogmen who brought havoc to the biggest and mightiest battleships the world had known.
Unable to respond accept in the traditional self defense of amassing soldiers along the river front, Italy had to do something special and out of the ordinary to show that its vulnerability was not entirely pitiful. Italy's strategy was to acquire the capability of inflicting sizeable damage to the Austrians where and when they would least expect it.