Type approval for Wärtsilä tunnel thruster

Wärtsilä's WTT11 tunnel thruster has received type approval from Lloyd's Register Wärtsilä's WTT11 tunnel thruster has received type approval from Lloyd's Register

Wärtsilä has received type approval from Lloyd’s Register for its WTT11 tunnel thruster. The approval means thrusters will not be subject to a design review for each vessel or hull number, with major cost saving implications.

The final step in the approval process involved a production quality assurance (factory audit) at the thruster manufacturing facility in Wuxi, China. The factory is now recognised as being able to produce these thrusters according to the design specification and test plans – the first time a Chinese producer of thrusters has been part of a type approval certificate from Lloyd’s Register (LR).

This is also the first time that a complete tunnel thruster has been considered for an LR type approval. The design review of the WTT11 covered the entire thruster system and its options, not just the components, and is applicable to the variants in the new portfolio of Wärtsilä thrusters. The design review was approved in December 2014.

"The factory audit is comprehensive and very demanding and we are delighted that the Wuxi factory has passed the audit for the new WTT portfolio with flying colours. This is a clear endorsement of the quality of both the product and the manufacturing process," said Arto Lehtinen, vice president, Propulsion, Wärtsilä Ship Power.

Flans Kemp, global business development leader for type approval at Lloyd's Register added: "With our new type approval procedure we were able to work together with Wärtsilä in tailoring the certificate exactly to the requirements outlined at the start of the entire process.”

The WTT series covers variants up to a maximum power rating of 4,500kW. The type approval is applicable for all WTT11 options, up to 1,100kW, and can be used as an example for the other sizes within the series. The WTT11 is e-motor driven and can be delivered with either a controllable pitch or fixed pitch propeller.

The hydrodynamic performance of each thruster unit is optimised based on state-of-the-art Computational Fluid Dynamics (CFD) analyses. The design complies with the latest requirements regarding environmentally friendly lubrication and has been comprehensively tested in Wärtsilä's full scale test facility in Tuusula, Finland.

Wärtsilä Propulsion (Wuxi) Co is Wärtsilä's first wholly-owned production facility in China and focuses on the manufacture of transverse thrusters, as well as seals and bearing products for all kinds and sizes of marine vessels. The company was established in 2004.


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