Bow rudder of cavitator attached with a non-symmetric anti-roll fin for strong manoeuvring underwater supercavitating vehicles

The hydrodynamic control of strong manoeuvring supercavitating vehicles (SVs) is challenging because unwanted changes in the aft planning contacts may result in destabilising forces and moments. In this paper, the disadvantages of the existing hydrodynamic layout of stern rudders are revealed. A novel hydrodynamic layout was proposed using a non-symmetric anti-roll fin installed to the lower part of a conical cavitator bow rudder to create high agility SVs. The conical cavitator bow rudder with two degrees of freedom in the vertical and horizontal planes was employed to manoeuvre pitch and yaw. Deflecting together with the cavitator, the anti-roll fin generates most of the anti-roll moment. The differential motion between the anti-roll fin and the cavitator provides the small residual moment. Adopting this layout, finless SVs could be designed, and the efficiency of the rudder system was remarkably improved. Simulations of an SV validated the effectiveness of the proposed layout.