Abstract
Large-Format Additive Manufacturing (LFAM) presents a transformative opportunity for the marine sector, particularly in accelerating the development of emerging marine renewable energy technologies, which are often hindered by high capital and prototyping costs. LFAM enables the fabrication of complex, large-scale components with reduced tooling and lead times, offering potential cost reductions above 50% compared to conventional manufacturing methods. While LFAM is experiencing rapid adoption and standardisation in other industrial sectors, its transfer to marine engineering remains severely underexplored. The absence of a consolidated, marine-specific methodology currently bottlenecks the transition from prototyping to functional, industrial-scale production. The central motivation of this review is to bridge this critical gap. Therefore, this paper covers LFAM technologies, previous case studies on marine application, identifying suitable materials for the marine environment, and outlining key design and fabrication aspects. The study reviews the operational requirements, dimensions, and loads for MRE structures and small vessels within the context of LFAM. It critically analyses the hydrodynamic impact of surface roughness, differentiating between applications tolerant of as-printed finishes (e.g., wave energy converters) and high-Reynolds cases (e.g., tidal devices, planing vessels) where smoothing is essential to prevent performance degradation. A structured, seven-step methodology is proposed, encompassing material and technology selection, design approaches, printing strategy, post-processing, and certification. Additionally, specific energy and cost metrics are evaluated to support techno-economic assessments. The review and an overall critical analysis demonstrate the feasibility of LFAM for producing functional marine components. Key trends are identified, highlighting future research directions and immediate industrial applications, and laying the groundwork for scalable, cost-effective, and sustainable manufacturing solutions in the MRE and broader marine sectors.