The Wärtsilä 46DF is a four-stroke dual-fuel engine that can be run on natural gas, heavy fuel oil (HFO) or marine diesel oil (MDO).
The engine can smoothly switch from gas fuel to HFO/MDO operation and vice versa without loss of power or speed. The Wärtsilä 46DF design is based on the well proven and reliable Wärtsilä 46F and Wärtsilä 50DF engine families, which have operated successfully on the market since the early 2000s. Both engines have an outstanding track record, with more than 800 engines in operation and over 11 million running hours experience using Wärtsilä’s leading DF technology.
The Wärtsilä 46DF has extended Wärtsilä’s dual-fuel engine family by covering the power range from 6.2 MW to 18.3 MW at 600 rpm.
Wärtsilä’s proven dual-fuel technology enables owners and operators to choose both gas and liquid fuel, and switch between the two according to cost, availability, and local environmental regulations.
The switch between fuel types is made without loss of power or speed. The engine automation adapts automatically to the relevant fuel selection, both in normal and emergency modes.
In gas mode, the natural gas is fed to the engine at low pressure. This facilitates a simpler and space-saving engine room configuration while providing easier and faster maintenance activities.
The engine’s gas piping is double-walled as standard, and the advanced integrated automation system enables enhanced safety and local monitoring. This leads to safer and more reliable operations, under all conditions. The complete built-in automation minimizes the need for external controls, thus saving engine control room space.
The Wärtsilä 46DF is designed for a broad range of marine applications. Thanks to its fuel flexibility and modular, compact design, the engine can be optimized for constant-speed diesel-electric operation. It also meets the need for direct drive main engine propulsion, operating at either constant speed or along a combinator curve. The multi-fuel operation capability offers new machinery opportunities for various vessel applications.
Three new LNG-fuelled Ro-Pax vessels being built for Swedish ferry operator Stena RoRo will feature a broad scope of Wärtsilä solutions. The ships are under construction at China Merchants Jinling (Weihai) Shipyard and will operate with Wärtsilä engines and propulsion machinery when delivered in 2024 and 2025. The order was booked with Wärtsilä in Q4 2021.
Having a single supplier of a large scope package provides multiple benefits in the form of system compatibility, and seamless interfacing during the procurement phase of the project. This notably lessens the risk of project delays.
“We are very familiar with Wärtsilä’s ability to supply reliable and highly efficient solutions in line with our operational and sustainability requirements. In particular, their experience and leading know-how in LNG technologies is especially important to us as we move to decarbonise our services,” says Per Westling, Managing Director, Stena RoRo.
“We are delighted to help Stena RoRo bring the latest new vessels in its E-Flexer series to market, and to work once again with Wärtsilä to ensure these vessels have highly efficient and environmentally sustainable propulsion,” said Ni Weisong, Vice General Manager, China Merchants Jinling (Weihai) Shipyard.
“We have earlier supplied a similar scope of solutions for Stena newbuild projects, and it is especially gratifying to receive this repeat order. The cooperation between our companies and with the shipyard has been excellent, and we look forward to another successful outcome,” says Roger Holm, President, Wärtsilä Marine Power.
The vessels, each around 200 metres long, are part of a series of E-Flexer class ferries ordered by Stena RoRo for European line service. For each ship Wärtsilä will supply Wärtsilä 46DF dual-fuel main engines, Wärtsilä 20DF dual-fuel auxiliary engines, two gearboxes, two controllable pitch propellers (CPP), the tunnel thrusters, and the fuel gas supply system.
The use of LNG as a marine fuel is viewed by Wärtsilä as being an important transitional solution in the drive towards decarbonising shipping. LNG bridges the gap between conventional diesel fuels and future zero-carbon alternatives yet to be widely available, a decarbonisation strategy fully supported by both Wärtsilä and Stena Line.
Wärtsilä is working closely with Stena RoRo to ensure that one of the vessels meets DNV’s Silent-E class notification. This recognises that underwater noise from the vessel is controlled to protect vulnerable environments and involves careful configuration and design of propulsion and onboard equipment to offer low noise while maintaining high efficiency.
Wärtsilä will also supply the ships with Nacos navigation and automation, as well as integrated control alarm and monitoring system MCS Platinum together with the performance monitoring system. The vessels will also feature Wärtsilä’s Smart Panoramic Edge Camera System, eliminating blind spots and creating a 360°, birds-eye view of the ships surroundings, offering a significant advantage when docking.
The equipment is scheduled for delivery to the yard commencing in Q4 2022.
Stena RoRo specialises in custom-built vessels, as well as standardised RoRo and RoPax vessels. The company leases about fifteen vessels to operators worldwide, both to other Stena companies and third parties. Stena RoRo specialises above all in applying its technical expertise to the design and production of new ships and the conversion of existing ships for delivering tailored transport solutions to its customers.
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Image caption: Wärtsilä will provide dual-fuel engines and a wide range of other systems to three more E-Flexer vessels under construction for Stena RoRo © Stena RoRo
Wärtsilä in brief
Wärtsilä is a global leader in innovative technologies and lifecycle solutions for the marine and energy markets. We emphasise innovation in sustainable technology and services to help our customers continuously improve their environmental and economic performance. Our dedicated and passionate team of 17,500 professionals in 200 locations in more than 70 countries shape the decarbonisation transformation of our industries across the globe. In 2020 Wärtsilä’s net sales totalled EUR 4.6 billion. Wärtsilä is listed on Nasdaq Helsinki.