Jack, this is how to use a Hawaiian Sling.
You hook the rubber band between your thumb and forefinger, and hold onto the pole in your palm. You then push the pole back in your palm, until the rubber band is fully stretched, and you are now holding toward the tip of the pole. Usually, by now the pole is arched into a long curve behind your hand.You keep a tight grip on the pole, swim close to the target (the fish, aka dinner), and let go of your grip, and you now have your dinner.You just have to remember that you need a lot of room to use one of these things, the whole length of the pole, all arched. Also, your target can't be further away then the length of the pole.A spear gun of any kind will have a trigger, and the spear is short. And when fired, the spear actually leaves your hand, or the gun.Jack: are you the same Jack that I know? We both worked as IT consultants for a Federal Way company? /John.Sorry Phil, I deviated from the original topic, but this is more fun than talking about firearms anyway.