SPOTLIGHT: The challenges of retrofitting diesel ships

‍The objective

To retrofit GREEN PIONEER, a platform supply vessel built in 2012, so that two of its four engines were able to run on ammonia. The aim was to demonstrate the viability of ammonia as an alternative to fossil fuels

Solis Marine was commissioned in late 2021 to provide naval architecture and design engineering services for the integration of Fortescue’s ammonia fuel technology with the vessel’s existing structure.

Our remit involved the provision of design engineering for the Fuel Ready notation which was awarded by the classification society DNV in early 2022.

To deliver this project within an ambitious timeframe, we assembled a team of experienced naval architects, structural engineers, design engineers, ventilation specialists and DP (dynamic positioning) experts based in both our Singapore and UK offices.

Technical approach

Our initial concept work addressed the following:

• · Concept design of tank connection space following assessment of toxic and hazardous zone requirements.
• · Aft deck layout of ammonia fuel tank and equipment spaces in line with DNV requirements.
• Stability assessment.
• Concept drawings for fuel system arrangement, fuel control and piping systems, propulsion and steering arrangements, electrical arrangement, leak detection and fire safety arrangements.
• Preparation of shipyard specification document for conversion to gas fuelled ammonia notation.

We then continued to work with Fortescue on the subsequent detailed design and conversion phases of the project. This required:

• Detailed design drawings for fuel system arrangement, hazardous areas and ammonia risk zones.
• Detailed design of tank connection space, scrubber space, air locks and bunkering station.
• Detailed design of vent mast on aft deck.
• Detailed design of ammonia fuel tank foundation and system to allow for thermal expansion of fuel tank during operations.
• Detailed design of structural fire protection, fire extinguishing system and water deluge system for ammonia fuel equipment.
• Detailed design and specification of ventilation system for tank connection space, scrubber space and air lock.
• SCR installation – structural modification drawings and installation procedure.
• Various vessel structural modifications to relocate air vents and escape hatches.
• Concept and structural design of the lifeboat platform and detailed drawings for construction.

Throughout the project, we liaised directly with DNV regards the submission of documentation, revisions, responses to comments and the final approval of documents requirement for ‘Gas Fuelled Ammonia’ notation.

Outcome

Fortescue spent 18 months developing the systems, processes and technology needed to safely run the GREEN PIONEER as a green ammonia dual-fuel ship.

Following completion of a fuel trial, the GREEN PIONEER has now received flag approval from the Singapore Registry of Ships (SRS) and the ‘Gas Fuelled Ammonia’ notation by DNV to use ammonia, in combination with diesel, as a marine fuel.

The successful culmination of this project reflects Fortescue’s commitment to drive innovation and co-operation across the industry, a vision we share as we continue help our clients achieve their decarbonisation objectives.

For further information email r.blazejczyk@solis-marine.com

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