Wärtsilä powers ammonia carrier duo

The two 51,350 cubic metre capacity vessels are being built by Nantong CIMC Sinopacific Offshore & Engineering in Shanghai for Navigator Amon Shipping, a joint venture between Navigator Gas and Norway-based Amon Maritime.

Under the contract, Wärtsilä will provide its Wärtsilä 25 Ammonia auxiliary engine, together with a selective catalytic reduction system, gas valve unit and a controllable pitch propulsion solution designed to improve operational efficiency and reliability.

The engine order was booked during the second quarter of 2026, while the propulsion system order followed in the third quarter.

“Wärtsilä has demonstrated industry-leading capabilities in enabling future low and zero-carbon fuels to become viable,” said Kaj S. Pilemand, director of Vessel Operations at Navigator Gas.

“By selecting the Wärtsilä 25 Ammonia engine, we expect to dramatically reduce the ships’ environmental impact, while supporting compliance with evolving regulatory requirements.”

Ammonia is increasingly viewed as one of the most promising carbon-free marine fuels as the industry works towards the International Maritime Organization’s target of net-zero greenhouse gas emissions by 2050. Wärtsilä introduced the marine sector’s first commercially available four-stroke ammonia-fuelled engine in 2023.

READ MORE: Wärtsilä pivots to ammonia

According to Wärtsilä, operating the engine on sustainable ammonia can reduce total greenhouse gas emissions by at least 90% compared with equivalent diesel engines, while the integrated propulsion system is designed to enhance efficiency and minimise emissions.

“This project reflects the continued momentum behind carbon-neutral and zero-carbon fuels, with ammonia emerging as one key pathway,” said Stefan Nysjö, vice president of Power Supply at Wärtsilä Marine.

“It also highlights the growing demand for flexible propulsion solutions that support new, more sustainable operating models.”

Delivery of the Wärtsilä equipment to the shipyard is scheduled to begin in June 2027.