Multi-objective maritime vessel routing with safety considerations: A trade-off analysis

This paper presents a large-scale, data-driven case study using real operational and meteorological data to optimize maritime vessel routing by jointly considering fuel consumption, voyage time, and safety risks under diverse environmental conditions. A multi-objective optimization framework based on a weighted-sum approach was applied to systematically capture trade-offs among objectives. In practice, selecting appropriate objective weightings, particularly for safety, is challenging, as planners often lack quantitative guidance on their operational implications. This study addresses that gap by evaluating a broad range of weighting scenarios and identifying when safety criteria have minor, moderate, or major impacts. Five major safety issues, namely dynamic stability, bow slamming, green water on deck, and newly developed parametric rolling and surf-riding/broaching-to risk functions, were incorporated through combined critical and non-critical penalties. The case study covered multiple global routes over an entire year and across different vessel sizes and loading conditions. Results show that moderate safety weighting reduces total risk by 30–35% with only a 1–2% increase in voyage cost, while further safety prioritization yields diminishing economic returns. The framework also provides a transferable methodology for systematic parameter selection, supporting transparent and practical multi-objective decision-making in maritime routing.