The 75m Atair will replace her 30-year-old namesake, and will be the first German research vessel operating on LNG fuel. Wärtsilä will also supply the engines and SCR systems for three German Federal police boats to be built at the Fassmer yard.

The full scope of Wärtsilä’s supply for Atair is two 6-cylinder Wärtsilä 20DF dual-fuel engines capable of running on either LNG or conventional liquid fuels, one 6-cylinder Wärtsilä 20 engine, two exhaust cleaning systems, and a Wärtsilä LNGPac fuel storage, supply, and control system.

Natural gas is supplied to the engine through a gas valve unit, where the gas is filtered and gas pressure is controlled. The system includes the necessary shut-off and venting valves to ensure safe and trouble-free low pressure gas supply. On the engine, the gas is supplied through a large common-rail pipe running along the engine. Each cylinder then has an individual feed pipe to the gas admission valve on the cylinder head. Gas piping is of double wall design as standard.

When running the engine in gas mode, the air / gas mixture is ignited with a small quantity of MDO pilot fuel, less than 1% of full-load fuel consumption. The amount of pilot fuel is optimized for best combustion by the embedded engine speed & load control and monitoring system.

The advanced automation system provides complete engine safety system and local monitoring.

The Wärtsilä LNGPac system is based on an IMO type C LNG storage tank with either double-walled vacuum or single-walled polyurethane insulation. Bunkering takes place from the bunkering station to the LNG tank via an insulated pipe. All necessary process equipment is installed in a separate unit which can be either mounted directly to the LNG tank or placed remotely from the LNG tank. The main process equipment ensures correct gas temperature and pressure for the engines and other gas consumers.

The engines will have Tier III classification since the dual-fuel engines comply with this classification when running in gas mode, and all the engines will be compliant when operating on diesel because of the Wärtsilä SCR systems. Furthermore, the engines will be double elastically mounted to minimize the noise. This special Wärtsilä technique will enable the ship to fulfil the DNVGL classification society’s ‘Silent R’ rating, thus allowing the sonar equipment to be used without disturbance from underwater radiated engine noise.

Our dual-fuel technology is unique when it comes to small bore medium speed engines, and the extended service intervals and economic fuel consumption of the Wärtsilä 20DF engine enable lower operating costs than is possible with high speed engines. We have worked closely with the Fassmer shipyard and are proud to have once again been selected to supply the machinery and equipment for this important project.

—Lars Anderson, Vice President, Engine Sales, Wärtsilä Marine Solutions

The Wärtsilä equipment is scheduled to be delivered to the yard in mid-2018, and the vessel will enter service in early 2020.

Earlier, Wärtsilä supplied double elastically mounted main engines equipped with SCR for the Sonne—a deep sea research vessel also owned by the German government.