Stena’s new Ro-Pax vessel, Ala’suinu, equipped with Wärtsilä propellers has received DNV’s Silent(E) notation, issued to vessels that demonstrate the ability to effectively reduce emissions of underwater radiated noise.Technology group Wärtsilä has designed and delivered controllable pitch propellers for Stena’s new Ro-Pax vessel, Ala’suinu, which has successfully completed sea trials.