Van der Velden Marine Systems’ retractable flanking rudder systems

Van der Velden Marine Systems (VDVMS) has developed and installed a retractable flanking rudder system to improve manoeuvrability during astern operations, while maintaining efficiency going forward.

The system, which was installed on the ‘Herkules XVII’ and ‘Herkules XVIII’, will first be used in Paraguay.

VDVMS developed the system and had it tested independently by the Development Centre for Ship Technology and Transport Systems (DST) in Duisburg (DE).

Flanking rudders are often used for inland river tow boats. They are located forward of the propellers in order to provide manoeuvrability during astern operations, giving the convoy control when backing or flanking.  

In practice flanking rudders are only required during a small percentage of the sailing time and when not in use they can produce drag and create turbulence to the inflow of water to the main propellers. By retracting the rudders when not in use, the issue is avoided.