The unrotated-projectile rocket launcher was an especially ill-conceived antiaircraft measure. Created to protect ships from enemy planes, the unrotated projectile was fired from a ship, and, upon reaching 1,000 feet in elevation, it would explode and disperse mines attached to parachutes via 400 feet of cable. The general idea was to create an aerial minefield wherein enemy planes would become ensnared in the mess of cables, pulling the mines into their fuselages and downing the plane. However, the mines, cables, and parachutes were all easily visible and enemy pilots had no trouble flying above or below the "aerial minefield". The undetonated mines would then be at the mercy of the wind, and they would often float back down toward the British ships that fired them."There are no records of UPs bringing down any aircraft. It's entirely possible that this system injured or killed more Britons than enemies due to accidents, fires, etc," according to a page dedicated to one of the battle cruisers that carried the weapon. The real history of it from https://www.businessinsider.com/the-5-most-bizarre-weapons-of-world-war-ii-2015-7 it is a great website