Could these be used as a ballast system? They are selling pool toys at my local hardware store and I wonder if one can use the basic watergun to create a working ballast system. The Super Soakers are water guns that are equipped with a water reservoir working in conjunction with a pump (or more of a syringe), you pump air into the tank to increase the water pressure and then press the trigger to release water. If you can pump water into the tank instead of air, and them find a way to release the pressure, and you have the basic pneumatic system layed out, maybe you can create a working ballast tank?