It can be difficult to get waterborne objects to go in the right direction -- just ask any boat captain who has had to fight waves on a choppy sea. However, researchers at the Australian National University have developed a "tractor beam" (really, a wave generator) that would make it trivial for you to float anything to its intended destination. The system creates complex 3D waves that have their own currents, letting you pull a target simply by adjusting the waves' frequencies and sizes. In fact, you can produce any flow you like; scientists in the lab made vortices on demand.
Via: Phys.org