Compressed air water cannon

I recently saw a compressed air "spud gun" fire a charge of water. Very cool, and my inspiration here.

These water cannons are to be mounted poolside at large waterparks. They look like air defense guns, with long transparent barrels and a shield seperating the barrel from the gunner. The shield in this case is actually to make it difficult for gunners to monkey with the barrels.

The barrels extend out over the pool. They can be swung around to some degree, but cannot be tipped down to horizontal.

The barrels have attached hoses and steadily fill with water. The guns are attached to compressed air hoses as well which charge them. On pulling the trigger, a burst of compressed air comes out through the barrel, expelling all accumulated water in a mighty surge.

The guns cannot be aimed directly at people in the pool, and so to soak someone the water must be arced up and down. This avoids the possibility of harm from high velocity water. Gunners can wait until the barrel is full and unlease a large volume at once, or shoot multiple small bursts.

The main danger is that potatoes, poop, or other solids get inserted into the barrels and fired out. This is the reason for the shields, and also the length of the barrels. Pool monkeys seen clambering out onto the barrels, potato in hand, will be made to eat the potato then evicted from the pool.