RINA unveils Mermaid, a future-ready ship design for an uncertain decarbonisation future

RINA has introduced Mermaid, a future-proof ship propulsion concept aimed at reducing fuel consumption, cutting emissions, enhancing operational resilience, and preserving long-term asset value in an ever-evolving decarbonisation landscape. This innovative design maximizes the potential of a vessel's efficient two-stroke main engine, transforming it into the ship's primary onboard power source, thereby diminishing reliance on less efficient auxiliary engines.

Mermaid integrates a shaft generator, propeller shaft clutch, and battery energy storage into a novel propulsion architecture that boosts efficiency without locking owners into a specific fuel pathway.

When a vessel docks, the propeller disconnects while the main engine continues to generate electrical power. Contrary to relying on auxiliary engines to meet onboard demand, Mermaid empowers the main engine to deliver electrical power directly or charge batteries. Upon full battery charge, the main engine operates more efficiently, resulting in reduced fuel consumption, lower emissions, and decreased operating costs.

Additionally, Mermaid bolsters propulsion systems by optimizing power distribution as vessels increasingly operate at slower speeds. This hybrid propulsion scheme allows for better alignment of propulsion power with actual operational conditions while maintaining flexibility and safety, thereby minimizing the need for oversized engine capacity and providing an extra electrical power source to bolster resilience during critical operations.

RINA's assessments reveal that Mermaid could cut fuel consumption by over 1,000 tonnes per year in certain applications, further diminishing fuel use and emissions and subsequently diminishing future compliance expenses while aiding shipowners in safeguarding long-term asset value. This fuel-agnostic concept grants owners enhanced flexibility as future regulations and technologies continue to evolve.

Moreover, batteries embedded within the concept promise significant safety advantages by enhancing onboard power resilience and curtailing the risk of power loss, both for propulsion and electric systems, during critical operations.

Antonios Trakakis, RINA's Energy Transition Solutions Technical Director, emphasizes that shipowners currently face the challenge of choosing a fuel, particularly as future solutions may emerge beyond current considerations. The maritime industry must prepare vessels for an unpredictable future, as many ships ordered today will operate well into the 2050s, necessitating commercially and technically sound decisions for decades.

Mermaid offers immediate operational and commercial benefits while mitigating the need for expensive future modifications. Rather than tailoring vessels to a singular decarbonisation scenario, the concept provides a flexible platform adaptable to evolving technologies, fuels, and regulations, ensuring value regardless of the maritime energy transition's trajectory.

Trakakis highlights that no consensus exists on future fuel dominance, and owners are presented with multiple pathways, each carrying distinct risks and uncertainties. Mermaid was engineered to function seamlessly irrespective of the future's direction. If the world changes, the ship remains ready; if it does not, the economics still prevail.

This design strategy across diverse vessel types, including tankers, bulk carriers, and container ships, is being refined into a comprehensive detailed design following positive feedback from both shipowners and shipyards. By emphasizing adaptability over a single fuel pathway, Mermaid illustrates how ship design can enable owners to reconcile commercial performance with long-term decarbonisation objectives, aligning with RINA's dedication to crafting pragmatic engineering solutions.