Z Batteries were a form of anti-aircraft rocket used mostly by the Home Guard in WWII. The system was known as an Unrotating Projectile and launched small mines on a parachutes with trailing wires that hopefully would tangle with enemy Aircraft. Various sites around the Clyde had them but it is thought this location might have been for training. During the war the nearby harbour at Ardrossan was taken over by the Admiralty and known as HMS Fortitude. All that remains are the steel mounting plates.
