Vad är hydroplane? Vad är hydroplane? See seaplane.A motorboat designed so that the prow and much of the hull lift out of the water and skim the surface at high speeds.See hydrofoil. A horizontal rudder on a submarine.To drive or ride in a hydroplane.To skim along on the surface of the water.To be or go out of control by skimming along the surface of a wet road. Used of a motor vehicle.