Diesel gensets for Lindblad Expeditions' new polar vessel under construction at Ulstein Verft have been prepared for low-noise operation.
Four gensets – designed by VMS Group and including two eight-cylinder L250 and two 12-cylinder V250 engines from GE Transportation - have been delivered to the Norwegian yard after configuration and testing in Denmark.
VMS Group has worked with Ulstein to prepare the generator sets to meet class society DNV GL’s ‘Silent E’ and ‘Comfort’ class notations, which place strict limitations on how much noise and vibration can be heard and felt in passenger areas.
VMS Group senior project manager Claus Bak Pedersen said that the notations posed a challenge for shipyards and integrators. “The class notations are for accommodation. But how much of that noise comes from the engine room? When you have a ship that is 120 m long, the noise can come from anywhere. That challenges the shipyards to look at all aspects.”
The company minimised the noise from engines by using double-resilient mountings, with rubber dampers between the engine and foundation as well as the foundation and the hull interior. Further damping was deployed at connections between the engine, coupling and generator.
Other design changes were needed to account for the extra friction caused by the rubber dampers. Although the GE Transporation engines vibrate very little during normal running, Mr Pedersen said that the flexible connections in piping needed to be stronger and longer to accommodate greater movement caused by shock absorption when engines are stopped and started.
“Vibrations mean you will get a lot of noise transmitted through the hull, not just airborne noise from the engine,” he said. “The challenge has been to take every component and isolate it as much as you can, from the couplings to the resilient mounting, the frame and the hull.”
VMS Group delivered generator sets for the first Lindblad vessel in April. In May, Lindblad exercised an option for another vessel. A second option for a third vessel is pending.
In preparation for the Lindblad contact, VMS Group built a generator testing facility where it can test assembled gensets before they are shipped to be mounted in vessels. The company is now renting out to third parties. The test hall in Frederikshavn, Denmark is available to all engine, generator and related equipment suppliers.
VMS Group chief commercial officer Kim Rasmussen said that the company decided to open the new facility when it became clear that testing would be needed for engines sold as part of its German and Scandinavian agency with GE Transportation.
“We have not encountered any other European facility that can offer these independent test runs,” he said.