Switzerland-based engine maker WinGD has confirmed it will supply the engines for a pair of ammonia dual-fuelled aframax tankers to be built for MISC group subsidiary AET.

AET placed the order for the vessels with China’s Dalian Shipbuilding Industry Co (DSIC). Both DSIC and WinGD are owned by China State Shipbuilding Corp.

It brings WinGD’s confirmed orderbook up to 10 ammonia dual-fuel engines.

The engine maker said it has secured orders for its 52-bore and 72-bore ammonia dual-fuel engines for ammonia carriers and bulkers and will have both engine sizes ready in 2025.

The two AET tankers will each have a six-cylinder, 62-bore engine, which WinGD said it will have ready in 2026 along with other engine sizes depending on market demand.

The bore size represents an engine cylinder’s diameter in centimetres.

WinGD’s new two-stroke ammonia and methanol engines operate according to the Diesel cycle, whereas its established LNG and diesel-only engines use the Otto cycle.

Its main competitor, MAN Energy Solutions, has two-stroke engine designs using the Diesel cycle, apart from its latest ME-GA gas engines which use the Otto cycle.

“First adopters of ammonia fuel are signalling confidence in the viability of both the fuel and the technology to use it,” WinGD director of sales Volkmar Galke said.

“We have been working closely with AET since last year to bring this order to reality. This order, backed by our string of AiPs [agreements in principle] for our safety concepts and fuel supply system design shows that WinGD is leading the way in bringing carbon-free ammonia power to the deepsea fleet.”

Last year, WinGD said it would be the engine supplier for a pair of ammonia carriers being built for Exmar at Hyundai Mipo Dockyard. It was the technology group’s first entry into the ammonia-fuelled gas carrier market.