but that think that goes back and forth in the line is powered by something isn't it?,(reply>), ah ok I get it now, it's just that the way the line goes from the boat to the the ring seemed a bit odd, kind of more parallel to the boat than I expected,(reply>), The boat's rudder pushes against the water, effectively turning the direction of the force by 90 degrees.,(reply>), Its just a ring. It works the same way as your shower curtains, it just slides on the wire to keep the boat from going backwards.<br><br>Think about how it would work if the boat had a sail, the air would push it backwards but the wire keeps it from drifting away. You can angle the sail so it pushed backwards left, or backwards right. Since you cant go backwards you only get pushed left and right.,(reply>), No, why would it need to?