Click on interactive overview on the left hand side of
this page.
If you have the Science Channel, you can see it demonstrated on Beyond Tomorrow, Episode 7. They do a comparo with a conventional stern drive boat, really cool technology.
The screws point forward, pulling the boat as opposed to pushing it, and the rudder, exhaust and propulsion are all co-located, so it gets a true horizontal thrust. Best of all, the entire unit turns in unison, so the boat can do a 360 and turn on a dime!
They rolled out this technology last year, but it's really hitting the market now.
JV