Quantitative Evaluation of Full-Scale Ship Maneuvering Characteristics During Berthing and Unberthing

TL;DR

This study provides a comprehensive full-scale analysis of berthing and unberthing maneuvers for a coastal ship equipped with vectwin rudders and a bow thruster, using data collected over roughly one year across five ports. By examining key quantities such as speed $U$, drift angle $\beta$, yaw rate $r$, obstacle distances, and actuator usage, the work reveals significant discrepancies between empirical behavior and conventional low-speed models, notably showing that the non-dimensional yaw rate $r' = rL_{pp}/U$ can reach values well beyond typical captive-model ranges. The results yield insights for refining low-speed maneuvering models (including MMG variants), adjusting captive model-test conditions, and informing digital twins and autonomous berthing/unberthing algorithms. The findings underscore the need for broader, multi-ship datasets and consideration of wind, currents, and port-specific factors to enhance the reliability and transferability of in-port autonomous operations.

Abstract

Leveraging empirical data is crucial in the development of accurate and reliable virtual models for the advancement of autonomous ship technologies and the optimization of port operations. This study presents an in-depth analysis of ship berthing and unberthing maneuvering characteristics by utilizing a comprehensive dataset encompassing the operation of a full-scale ship in diverse infrastructural and environmental conditions. Various statistical techniques and time-series analysis were employed to process and interpret the operational data. A systematic analysis was conducted on key performance variables, including approach speed, drift angles, turning motions, distance from obstacles, and actuator utilization. The results demonstrate significant discrepancies between the empirical data and the established maneuvering characteristics. These findings have the potential to significantly enhance the accuracy and reliability of conventional maneuvering models, such as the Mathematical Modeling Group (MMG) model, and improve the conditions used in captive model tests for the identification of maneuvering model parameters. Furthermore, these findings could inform the development of more robust autonomous berthing and unberthing algorithms and digital twins.

Figures (38)

• Figure 1: Coordinate systems. The origin of space-fixed $\mathrm{O}_{0}-X_{0}Y_{0}$ was set to the position of GNSS antenna at the moored position.
• Figure 2: Mean draft at midship
• Figure 3: Mean true wind speed.
• Figure 5: Windroses showing the distribution of true wind direction and speed for Ports A - E-1
• Figure 6: Relationship between the Euclidean distance $L_\mathrm{d}$ and arc length of trajectory $L_\mathrm{arc}$. Each line represents the individual log data.