A British firm has developed a non-lethal (most of the time) weapon for keeping Somali pirates from getting close enough to board your ship. The $23,000 "Somali Stinger" is a compressed air cannon that can fire a "shotgun shell" full of golf ball size projectiles, moving at up to 210 meters (650 feet) per second at targets up to 550 meters away. When hit by one of these projectiles, the victim will be hurt, but not seriously injured. The cannon can also fire nets (to entangle the propeller of the pirate's speedboat), or smoke grenades. If all this does not stop the pirates, it will at least entertain them.
Non-lethal weapons are important when you are dealing with Somali pirates, as these fellows are very media savvy. Kill some of them, and you will be criticized by a growing chorus of journalists who do not tolerate that sort of behavior. Maybe that's just professional courtesy, but it is the way it is.