Innovative retractable flanking rudder systems for two river tow boats

Inland river towboats are designed and built by Veka Shipbuilding to operate in Paraguay.

This innovative product brings remarkable new efficiency to the inland shipping industry. The retractable flanking rudder system is developed by the R&D department of Van der Velden Marine Systems (VDVMS) and independently tested in the Development Centre for Ship Technology and Transport Systems (DST) in Duisburg (DE) all to the request of Veka Shipbuilding (NL).

Flanking rudders are often used for inland river tow boats. These rudders are located forward of the propellers in order to provide manoeuvrability during astern operations. This gives 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 are parasitic only producing drag and creating turbulence to the inflow of water to the main propellers. Retractable flanking rudders, which are fully retracted in the hull of the vessel when not required, increase water flow to the propellers, reduce vessel drag and increase propulsive efficiency directly resulting in increased fuel savings.

In close cooperation with Veka and operator Imperial Shipping the VDVMS team designed, engineered and manufactured the retractable flanking units in less than 6 months. The hulls were built at the Veka location in Lemmer. Outfitting of the two vessels took place at Veka Shipbuilding in Werkendam. Together with Veka, VDVMS installed the prefabricated units into the hulls during outfitting.

These new and highly innovative pushers the “Herkules XVII” and “Herkules XVIII” will operate on the Parana river in Paraguay with maximum 12 barges of 61.50 meters long and 16.60 meters wide, providing a total loading capacity of +35,000 tons. Including the towboat with a length of 43.50 meters, a width of 17.50 meters and a depth of 2 meters, the entire convoy will measure 289.50 meters long and 49.80 meters wide.

Unprecedented powerhouses with 7 rudders and 5 independent steering gears!

In addition to the delivery of two retractable flanking units each with two high lift rudders and asymmetric steering gears, VDVMS has also supplied the main rudder system consisting of three HD240S high lift fishtail rudders with stainless steel reinforced leading edges. The vessel has five independently operating hydraulic power packs, three units which operate the three main rudders (3x 1 DW65/60) and two to retract and operate the flanking rudders (2x 2DWK 4060/35). All main rudders are independently operated and controlled by the VDVMS Triple SP2700 control panel, the flanking rudders are operated by two SP2700 NFU control panels.

To operate the flanking rudder lift units 2 HDMI touch screens (retractable flanking rudder operation and control system RET2700) have been installed. In addition, VDVMS supplied a proprietary follow up steering system to operate each rudder independently, and one FU2700 steering lever to operate all three main rudders synchronized. Van der Velden Marine Systems wishes the crews of the “Herkules XVII” and “Herkules XVIII” safe journeys and is confident that this “first-of-a-kind” retractable flanking rudder system will prove itself in these ultramodern tow boats.