ABS, HD Korea Shipbuilding & Offshore Engineering and Siemens have signed a memorandum of understanding at Gastech 2026 to build a digital twin platform that certifies ammonia-fuelled vessels during the design stage.

The three partners will combine computational fluid dynamics (CFD) with digital twin simulation to model how ammonia disperses after a bunker or tank leak. Designers will use the output to size ventilation, sensor placement and crew-protection systems during early-stage naval architecture work, rather than waiting for full-scale prototype testing.

The workload splits along existing core competencies. HD KSOE will develop the ammonia safety systems and run the experimental research underpinning the CFD inputs. Siemens will deliver the simulation engine and digital twin environment through its Digital Industries Software division. ABS, the Houston-based classification society, will translate the data into a safety assessment methodology that shipbuilders can submit alongside class approval drawings.

Why ammonia needs a digital safety case

Ammonia is one of the leading candidates to replace fossil bunker fuel on deep-sea tonnage, but the molecule's toxicity changes the risk profile. Even small releases must be modelled carefully, because ammonia vapour behaves differently from conventional marine fuels in confined machinery spaces, where crew exposure can become acute within seconds.

That risk profile has slowed ammonia newbuild orders. Designers cannot rely on the empirical safety data accumulated over decades for conventional fuels, and classification societies must review each fuel-gas system on a project-by-project basis. A shared digital twin that maps likely leak plumes for a given hull form, engine-room layout and bunker station can shorten that review cycle.

Patrick Ryan, ABS Senior Vice President and Chief Technology Officer, framed the project in operational terms. "By pairing CFD analysis with digital twin technology, this project gives designers a faster, more rigorous way to understand leak behaviour," he said.

What each partner brings to the yard

The collaboration rests on a division of labour that reflects each company's commercial position in the alternative-fuels supply chain.

• HD KSOE develops ammonia safety systems and leads the physical testing that feeds the CFD models for the joint programme.
• Siemens supplies simulation analysis and digital twin tooling through its Digital Industries Software division.
• ABS writes the safety assessment framework, the document a yard needs to obtain class approval for an ammonia-fuelled design.

The pact extends a wider alliance. Earlier this year, ABS and HD KSOE agreed to cooperate on digital engineering, autonomous vessel systems and cybersecurity. The ammonia digital twin adds a fuel-specific application to that broader R&D pipeline.

What shipowners and yards stand to gain

Carriers weighing ammonia newbuilds face a familiar commercial calculation. Dual-fuel ammonia machinery costs more than conventional main engines, and the safety case adds engineering hours. A pre-validated digital twin reduces the cost of design iteration, because the yard can test ventilation and detection layouts in simulation rather than on a physical mock-up.

For the wider freight chain, the timeline matters less directly, but downstream effects will show up in vessel availability. If classification can approve ammonia-fuelled designs faster, the orderbook for alternative-fuel tonnage should expand, easing the supply constraint that has kept early alternative-fuel newbuilds at a premium.

Where the project goes next

HD KSOE expects the same toolchain to spread beyond safety into broader shipbuilding R&D. Chang Kwangpil, Head of the Future Technology Institute at HD KSOE, pointed to AI integration as the next step. "We expect the integration of AI and digital twin technologies to accelerate further in the R&D field as well," he said.

The first deliverable from the three-party team is unlikely to be a commercial product in 2026. Classification rules still require physical testing for class approval, and ABS will need to integrate the digital twin methodology into its procedures for ammonia-fuelled ships. The commercial trajectory, however, points toward AI-assisted safety certification becoming an integral part of alternative-fuel newbuild workflows in the second half of the decade.