Photos: This boat swims like a dolphin

The Innespace Dolphin can speed along at 30 mph on the surface and 20 mph below. Like an airplane, it has 3-axis control (pitch, roll and yaw). Its underwater travel is limited, however, to only a few feet under the surface and durations of about 15 seconds; the company says deeper dives may be possible with the use of supplementary compressed air.