Paraguay push boats have retractable flanking rudders

JUNE 15, 2016 —Imperial Shipping, Paraguay, has ordered at the large Dutch Shipbuilder, Veka Shipbuilding BV, two new push boats, the Herkules XVII and Herkules XVIII, for operations on the Parana river, that are fitted with retractable flanking rudder systems, a mutual innovation by Van der Velden Marine Systems and Veka Shipbuilding. The system brings new efficiency to the inland shipping industry.

Veka Group and Van Der Velden developed the system and had it tested independently by the Development Centre for Ship Technology and Transport Systems (DST) in Duisburg, Germany.

Flanking rudders are often used for inland river tow boats. They are located forward of the propellers in order to provide maneuverability 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 are parasitic, producing drag and creating turbulence to the inflow of water to the main propellers.

Retractable flanking rudders increase water flow to the propellers, reduce vessel drag and increase propulsive efficiency, directly resulting in increased fuel savings.  

In close cooperation with the customer and the end-client Van der Velden and VEKA designed, engineered and manufactured the retractable flanking units in less than six months.

The Herkules XVII and Herkules XVIII will operate with a maximum of 12 (approx. 62  m x 17 m) barges, providing a total loading capacity of 35,000 tons. Including the push boat, the entire convoy will measure 290 m x 50 m.


The pushboats are described as "unprecedented powerhouses" with seven rudders and five 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 of which operate the three main rudders (3 x 1DW65/60) and two to retract and operate the flanking rudders (2 x 2DWK 4060/35). All main rudders are operated independently 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, two 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.

close up ruddes

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