I saw one at a shop in NC, and believe it or not, they were used for duck hunting. These monster were loaded on land and attached to a stationary pedestal located at the front of a very small one man boat. The intent was to ease up on a flock of ducks, point and fire! I saw a reenactment on PBS (minus the ducks), and the recoil pushed the boat back several feet in the water. Not to mention what the poor guy who shot the gun had to endure!