Van der Velden supplier of rudder system on Cotunav’s new ropax

Van der Velden Marine Systems delivered two Timon rudders for TANIT, the new RoPax ferry of la Compagnie Tunisienne de Navigation (CoTuNav). Tunisia’s state owned ferry company CoTuNav has chosen the Korean shipyard DMSE to build this new RoPax cruise ferry, which will be one of the biggest ferries in the Mediterranean when delivered in May 2012. What’s more, with a maximum speed of 30 knots, it will also be one of the fastest sailing ferries in the world.

The ferry is designed with two separate engine rooms with the propeller shaftlines having different lengths of well over 40 metres. The final propeller blade design will be hydrodynamically optimised and carefully balanced with a special focus on propulsion efficiency, low noise, and cavitation levels.

The Timon flap type rudders installed on the TANIT optimise speed and course corrections and reduce cavitation and vibration. The rudder profile is based on the well-known HSVA and NACA profiles and is very suitable for fast vessels requiring a high manoeuvring performance. Because of the flap, turning circles are smaller and course corrections can be made more efficiently.

The two Timon rudders are provided with Asymmetric Rudder Technology (ART™). ART™ is a special rudder design that has been developed to improve propeller flow. A special layout modifies the profile above and below the centreline of the propeller in such a way that effects of the rotation of the propeller slipstream are countered. This expands the cavitation-free rudder angle and reduces drag, which contributes to the ship’s speed abilities. Reduced rudder cavitation also gives an extended life span to rudders and shaft bearing systems. Low vibration and noise levels are an additional bonus.

The ship will measure 210m in length and 30m in width with a design speed of 27.5 knots and a capacity of 1060 vehicles and 3200 passengers. The ferry will service CoTuNav’s routes between Tunisia, Italy and France and will include a shopping centre, restaurants, swimming pool and multiple entertainment facilities.

Through this new ship CoTuNav seeks to consolidate its position in the Mediterranean sea transport, to further develop the quality of its services and to contribute to the promotion of Tunisian tourism.