Sustainable Marine Operations: Uncertainty-Aware Multi-Body Motion Analysis of Offshore Support Vessels
Abstract
Offshore support operations must balance safety and sustainability under highly variable sea conditions. Deterministic motion analyses can underestimate extreme vessel responses, leading to insufficient operational limits and increased environmental impact. We develop a fuzzy‐enhanced multi‐body dynamics framework in which key inputs significant wave height, peak period, added mass, and radiation damping are represented as fuzzy numbers. An α-cut decomposition yields interval bounds at each confidence level, and a fourth-order Runge-Kutta scheme integrates the six-degree-of-freedom equations of motion for both lower and upper “vertex” systems. A case study off the Karnataka coast applies both full 6-DoF and single-DOF heave approximations to demonstrate methodology. The heave response envelopes under calm (nominal α = 1: 0.73 m; full range at α = 0: 0.64–1.64 m) and severe (nominal 1.58 m; range 1.32–2.36 m) sea states reveal potential underestimations of 124 % and 49 %, respectively, when using only nominal values. By selecting an operational α-level (e.g., α* = 0.35 to cap heave ≤ 1.8 m), decision-makers can balance risk tolerance and conservatism. Sensitivity analysis identifies significant wave height as the dominant uncertainty driver. Computational trade-offs and adaptive α-sampling strategies are discussed. This work provides a self-contained, uncertainty-aware tool for deriving operational envelopes that improve risk-informed planning and enable fuel-efficiency optimization. By embedding fuzzy uncertainty quantification into vessel dynamics, the methodology supports safer, more sustainable marine operations and can be extended to real-time sensor fusion, multi-vessel interactions, and frequency-dependent hydrodynamics.