Wärtsilä has successfully passed the final step of the Lloyd’s Register (LRS) classification society’s Type Approval process to obtain an LR Type Approval Certificate for the Wärtsilä WTT11 tunnel thruster. Having Type Approval means that the thruster will not have to undergo a design review for each individual vessel or hull number. It is anticipated that the approval certification will deliver significant cost savings, as well as considerable reductions in production time, thereby giving a shorter lead time for the customer, the company said in its press release.
The WTT11 belongs to the company’s new generation portfolio of thruster solutions. This final step in the approval process involved a production quality assurance (factory audit) at the specific location where the thrusters are to be produced, namely the company’s dedicated manufacturing facility in Wuxi, China. The Wuxi factory is now recognised as being able to produce these thrusters according to the design specification and test plans. This is the first time ever that a Chinese producer of thrusters has been part of a Type Approval Certificate by LRS. The factory audit was carried out on May 15.
This is also the first time ever that a complete tunnel thruster has been considered for an LR type approval certificate. The first step towards approval was the design review (plan approval) in which the design was assessed as to its compliance with the technical requirements (LRS rules). The design review of the WTT11 covers the entire thruster system and its options, not merely the components, and is applicable to the variants in the new portfolio of Wärtsilä thrusters. The design review was approved in December 2014.
The new Wärtsilä WTT series of thrusters covers variants up to a maximum power rating of 4500 kW. The LR Type Approval is applicable for all WTT11 options and can be used as an example for the other variants (sizes) within the WTT series. The WTT11 has a maximum power rating of 1100 kW, is e-motor driven (suitable for several input speeds of the e-motor), and can be delivered with either a controllable pitch or fixed pitch propeller. The hydrodynamic performance of each thruster unit is optimized based on state-of-the-art Computational Fluid Dynamics (CFD) analyses. Furthermore, the design complies with the latest requirements regarding environmentally friendly lubrication. The thruster has been comprehensively tested in Wärtsilä’s full scale test facility in Tuusula, Finland.
Wärtsilä Propulsion (Wuxi) Co Ltd 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 and is located some 100 km west of Shanghai. The Wuxi factory serves not only the major East Asian shipbuilding countries, but also the entire global market, thereby enabling Wärtsilä to meet the fast growing demand in China, to improve efficiency, and to optimize the company’s global production.