New Energy-Saving Device: the Becker Twisted Fin

Becker Marine Systems continues to focus on energy savings.

 

The new product innovation for container ships and other fast vessels was developed with the combined expertise acquired from Becker rudders for fast ships and the Becker Mewis Duct  for slower vessels. Becker Marine Systems continues to offer advanced solutions to the maritime market and since 1946 has been renowned worldwide for improving the manoeuvrability of all types of ships. Furthermore, Becker Marine Systems has focused on energy savings and provides one of the most efficient energysaving devices for the maritime market with the Becker Mewis Duct. On average, power savings of over 6% could be achieved and by December 2012 more than 150 vessels have been equipped with the Becker Mewis Duct. In the last three years over 350 systems have been sold. Becker Marine Systems has reacted to the heavy demand of shipping companies for a similar device for faster vessels. After two years of research and based on three years operational experience with the Becker Mewis Duct  Becker Marine Systems has developed a new energy-saving device tailor-made for container ships and other types of fast vessels with bulbous stern – the Becker Twisted Fin.

The savings of the Becker Mewis Duct  are reduced at speeds above approx. 20 knots, which is why this solution is for slower ships such as tankers, bulk carriers and heavy load vessels. Becker Marine Systems is now introducing the Becker Twisted Fin  for faster ships with speeds above 18 knots. Like the Becker Mewis Duct , the Becker Twisted Fin  has no moveable parts, is also installed in front of the propeller and generates a pre-swirl. The system thus provides fast ships tangible energy savings. The nozzle ring is significantly smaller than that of the Becker Mewis Duct and has a special, flat profile with much lower drag. The fins familiar from the Becker Mewis Duct  on the inside of the nozzle ring extend outwards beyond the nozzle.

 

To prevent the formation of a swirl with cavitation at the ends of the fins Becker has developed special end caps for the fins. The small nozzle ring generates thrust, provides stability to the fins and reduces vibrations. Computational Fluid Dynamics (CFD) tests, model tests and full scale operation have shown fuel savings averaging 3% for container ships. Even better results can be obtained with the combination of a Becker Twisted Fin  and the Becker TLKSR  Twisted Rudder. The well-proven Becker Mewis Duct  business model will be continued with Becker Marine Systems’ guarantee of the vessel’s power reduction as verified by a model test. Each Becker Twisted Fin  system is individually designed according to hull geometry, propeller design and engine data. The design takes into account the newest strength, fatigue and vibration requirements from classification societies.

After the successful model test of the Becker Twisted Fin  prototype in early 2012, in June 2012 Becker Marine Systems had already signed a contract with Hamburg Süd to retrofit the Becker Twisted Fin  system on a series of ten 7,100 TEU container vessels. The tank tests were conducted at HSVA in Hamburg in October 2012 and the first installation took place at Damen Shipyard in Rotterdam in December 2012. The big challenge was the installation time of three days and a total docking time of five days. The complete installation was carried out during the normal class docking of the vessels. Following the first journeys, the measured power savings from the model test were able to be reproduced during the vessel’s operation. With Becker Marine Systems’ energy-saving devices, the Becker Mewis Duct  and the Becker Twisted Fin , customers are prepared to fulfil the newest EEDI regulations.

Benefits of the Becker Twisted Fin:
 

- Fuel savings of up to 3%
- Reduction of NOx and CO2 emissions
- Suitable for newbuildings and retrofits
- No moving parts, no maintenance required
- Fast installation
- Structural guarantee