I was just watching this thing with Hammond on the Discovery Channel about HMS Illustrious and it came to its defence system 'Goalkeeper'. Basically it's their last defence system when all else fails that takes out missiles. It's a 30mm, 7 barrel gatling gun that fires 70 rounds per second with a muzzle velocity of 1109 m/s (or 2480 mph). The turret will do a full 360 in 3.8 seconds! Then it showed some footage of it. First thing that come to mind was "F**K"!!!

Takes balls firing a missile at your own ship!!