GCMD: ammonia transfers technically and operationally feasible within Singapore’s port waters

Robust safeguards outlined, no high-level risks identified

Click to enlarge. Determination of safety zones for ammonia ship-to-ship transfers in Singapore port waters via QRA. Figure 8 from Vessel-, location- and operations-specific safety assessments for a ship-to-ship ammonia transfer in Singapore’s port waters (GCMD, Jan 2026).

In its new report, the Global Centre for Maritime Decarbonisation (GCMD) worked with industry partners to assess the feasibility of ammonia transfers between two handysize liquid ammonia carriers at Raffles Reserve Anchorage. Vessel-, location- and operations-specific safety assessments for a ship-to-ship ammonia transfer in Singapore’s port waters concludes that ammonia transfers are “technically and operationally feasible within Singapore’s port waters, provided robust safeguards are in place”.

QRA analysis established safety zones for ammonia ship-to-ship transfers, resulting in a “conservative” exclusion zone with a radius of 547m, shrinking to 312m in more favorable weather conditions. Combined HAZID and HAZOP workshops identified zero high-level risks, eleven medium-level risks (Tolerable if reduced to As Low As Reasonably Practicable, or ALARP), and twelve low-level risks (Broadly acceptable). The identified risks were primarily related to: “navigational and berthing challenges arising from adverse weather conditions, mooring failures, falling objects during lifting operations, containment breaches within tank and piping systems, and personnel transfer activities involving crew and observers”.

Focusing on local conditions, a series of operational recommendations for ammonia ship-to-ship transfers made by the authors includes:

• The effects of beam wind conditions, particularly during the southwest monsoon (June to September), should be incorporated into the mooring analysis.
• Operations should be suspended if visibility falls below one nautical mile.
• Although cross-currents are not known to occur at the anchorage, verification before each operation is recommended.
• For a first-time operation, pilots should remain onboard both vessels after the ammonia carriers are secured during mooring until departure to assist with any emergency unmooring or unscheduled departure procedures.
• Tug requirements should follow MPA’s towage guidelines. For vessels similar in size to the Navigator Aries and the Navigator Genesis, two tugs are recommended, with an additional standby tug stationed nearby throughout the operations.
• While preliminary analysis indicated feasibility, a full dynamic mooring analysis based on vessel arrival conditions is recommended to optimise mooring thresholds and provide operational guidance based on measured or hindcast data.
• A QRA and CFD evaluation are recommended to determine the safety zone. Accordingly, an MEZ should be established during bunkering operation to restrict passing traffic, except for permitted service crafts.

Operational recommendations for ammonia StS operations, from Vessel-, location- and operations-specific safety assessments for a ship-to-ship ammonia transfer in Singapore’s port waters (GCMD, Jan 2026)

Looking towards the first pilot operation in Singapore, the report authors have recommended that SIMOPs not take place in the first instance. Safe demonstration of simultaneous operations (e.g. fueling while also handling cargo on the vessel) remains a key readiness step still to take for ammonia bunkering.