ORCID

Abstract

Marine composite recreational craft are growing in number. Sectoral roadmaps for sustainable development are increasing pressure to demonstrate life cycle environmental performance. Life cycle assessment (LCA) has been identified as a key strategic decision support tool. However, current practice is undermined by sparse, non-representative data and methodological inconsistencies. These weaknesses increase the risk of biased or misleading interpretation, constrain wider uptake of LCA, and limit the sector’s ability to respond credibly to tightening environmental sustainability expectations. This thesis assesses the cradle-to-grave environmental impacts of a market-representative glass-fibre reinforced plastic (GRP) motor yacht across 16 impact categories. The research builds on primary life cycle inventory (LCI) data derived from process and energy mapping of industrial manufacturing lines and operating profiles, triangulated with literature case studies. In parallel, the first comprehensive background LCI data quality assessment for eight key composite materials across seven major databases identifies a major source of variability in LCA results. Methodological robustness was evaluated through Monte Carlo uncertainty analysis of data quality and variability, scenario analysis of manufacturing energy use, material use and waste, and eight operational profiles. Three life cycle impact assessment methods were used for completeness checks of uncharacterised elementary flows and sensitivity analysis. The use phase dominated the life cycle impacts (~90% of impacts in most categories over a sensible reference service life) driven by fuel combustion. The whole life cycle assessment also showed that the magnitude and ranking of life cycle stages and impact categories are strongly conditioned by methodological choices. Allocation of site energy based on lightship mass increased core-process climate change impacts by 87% and total 25-year impacts by 7% relative to the subdivided process approach used in most literature. Overlooked hotspots in many previous assessments included manufacturing (site energy, styrene emissions and inherent GRP/resin waste together increase human toxicity impacts by more than 50%), operations, and below-waterline effects (antifouling leachates materially shape marine ecotoxicity). Across the life cycle, marina shore electricity and maintenance flows (batteries, paints) are non-trivial, scenario-dependent and can exceed the contribution of upstream composite structural materials. This thesis identifies a set of key impact driving parameters: allocation-sensitive core energy, mass-sensitive process waste, styrene and combustion emissions, and profile sensitive use-phase burdens. This work sets out a current, sector-specific LCA framework that directly addresses gaps in environmental impact, methodological consistency, and background data quality that could limit global comparability and undermine the credibility of the assessment. This work reinforces the need to treat LCA as a living instrument that is regularly updated as non-characterised flows are quantified, data quality improves, decarbonisation technologies and sustainable operational practices evolve. These outcomes improve the robustness and accuracy of the life cycle environmental impact assessment.

Awarding Institution(s)

University of Plymouth

Award Sponsors

Princess Yachts ltd, Plymouth, UK

Supervisor

John Summerscales, Alexander Besinis, Jasper Graham-Jones, Richard Pemberton

Keywords

Life Cycle Assessment, Yacht, Composite, Environmental impacts, Environmental sustainability

Document Type

Thesis

Publication Date

2026

Embargo Period

2026-03-18

Deposit Date

March 2026

Creative Commons License

Creative Commons Attribution-NonCommercial 4.0 International License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License

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