The elimination of the contact area between the hull surface and the rotation direction of the star-shaped cross section remove the rotary friction in contrast to the old style screw vehicles.
The angular surfaces to the rotation direction can be rotated faster or slower to regulate the pressure on the surfaces. By rotating the star-shaped hull a little bit faster than the propulsion speed, it makes a constant low pressure in front of the screw grooves.
The constantly and controlled low pressure make foundation for a stabilized and high-efficiently supercavitation. The principle works like cavitating propellers, where the whole cavitation phenomen was detected. It's easy to make a controlled supercavitation with rotation by regulating the angular velocity.
ROTARY CONTROLLED CAVIATION
OLD-STYLE SCREW VESSELS
Fordson Snowmobile 1929:
Chrysler Marsh Screw Amphibian 1960's