Late in World War 1 a new weapon was developed that would become standard on most warships in the next
war. On Feb. 21, 1918 the Austrian submarine U-23 was on patrol in the Strait of Otranto when the Italian
torpedo boat Airone found the boat on the surface. Airone was carrying the precursor to the modern depth
charge, a device thrown overboard and towed behind the ship until it made contact with a target.

It was unwieldy, difficult to use and was only as accurate as the helmsman, in this case the helmsman was
dead on. After the boat submerged to avoid a ramming attack the captain of the Arione, Lt Cdr Klemens von Bezard, ordered the weapon deployed. The crew must have been well trained or perhaps just lucky because
the target was hit, exploded and sank with all hands. This was the first time a submarine was sunk using this
weapon.