Wärtsilä will supply 36 of its 34DF dual-fuel engines for twelve CMA CGM container vessels being built at Jiangnan Shipyard in China, alongside stern tube and line shaft bearings and Airguard sealing systems. Each ship will have capacity for 18,000 TEU and will operate on LNG.
Equipment deliveries are scheduled to begin in 2027. Wärtsilä booked the engine order covering all twelve vessels during the first quarter of 2026, while seals and bearings for the first four ships were booked in the same quarter and equipment for the remaining eight followed during the second quarter.
Three 34DF engines will be supplied for each vessel through CWEC (Shanghai) Co Ltd, Wärtsilä’s Chinese joint venture operation. Manufacturing the engines in Shanghai places production within the same national industrial base as construction of the ships at Jiangnan, reducing the distance between engine manufacture, yard delivery and installation.
The 34DF is a medium speed dual-fuel engine capable of operating on gas or liquid fuel. During gas operation, LNG stored at cryogenic temperature is vaporised and supplied to the engine as natural gas, while the ability to change fuel mode gives the vessel operational flexibility when fuel availability or other requirements change.
LNG can reduce carbon dioxide and conventional air pollutant emissions compared with oil fuels in marine engines, while methane escaping unburned through the engine or wider fuel chain can offset part of that benefit. Combustion behaviour, fuel handling and supply chain emissions therefore influence the overall climate performance alongside the lower carbon content of the fuel burned on board.
CMA CGM is applying the same engine family across twelve vessels, allowing installation, commissioning, crew training and spare parts planning to be repeated across the series. Wärtsilä also has an established installed base for the 34DF platform, giving operators and service teams existing experience of its maintenance and operating characteristics before the first of the new ships enters service.
Repeated machinery configuration can simplify yard work because engineers do not have to integrate a different auxiliary engine arrangement into each hull. Lessons identified during installation and commissioning of the early vessels can be incorporated into later ships, while recurring dimensions, interfaces and service requirements make procurement and production planning more predictable.
Each vessel’s 18,000 TEU capacity also places substantial continuous demand on auxiliary machinery. Pumps, cooling systems, navigation equipment, cargo systems and refrigerated containers all require electrical power during long voyages, so reliability of the generating plant affects both routine ship operation and the ability to support temperature controlled cargo.
Wärtsilä’s scope extends from those engines into the shaft line through stern tube and line shaft bearings and the Airguard seal system. Bearings maintain shaft alignment and carry loads created by the rotating shaft and propeller, while the seal controls the boundary where the shaft passes through the hull between lubricated machinery and seawater.
Airguard introduces an air chamber into that sealing arrangement to help separate lubricating oil from seawater and reduce the risk of leakage across the boundary. Bearings and seals are difficult to access during normal trading, making their condition important to vessel availability because major shaft line intervention can require substantial downtime.
Supplying engines, bearings and seals gives Wärtsilä responsibility across several connected parts of the machinery installation. Jiangnan will still integrate those systems into the overall vessel design, while common dimensional and operating requirements can be coordinated earlier because multiple components come from the same supplier.
The order also creates a repeated manufacturing programme at CWEC in Shanghai. Producing 36 engines against one vessel series allows purchasing, machining, assembly and testing to be planned around a known sequence, although delivery dates still have to remain aligned with construction of each hull so machinery reaches the yard when installation work is ready to begin.
Delays can propagate through a repeated programme because a production issue affecting one common component may also affect later vessels if it is not corrected early. The same repetition can accelerate corrective action, however, because findings from an early build can be incorporated into subsequent engines and installations without redesigning the entire machinery arrangement.
CMA CGM has continued adding LNG capable tonnage as it renews and expands its container fleet, and the twelve Jiangnan ships extend that strategy at substantial scale while retaining liquid fuel capability. Deliveries beginning in 2027 will link Wärtsilä’s manufacturing schedule with the shipyard programme over several years.
By the end of that sequence, 36 engines and associated shaft equipment will have been manufactured, installed and commissioned against one common vessel series. The repeated configuration provides efficiencies in production and service planning, while reliable execution will depend on keeping engine manufacture, equipment delivery and hull construction aligned across all twelve ships.
