The impact of cable length on the mobility performance of a remotely operated underwater vehicle (ROV)

This study examines the impact of tether length on the mobility performance of a Remotely Operated Vehicle (ROV) in calm-water conditions. Field studies were executed at Laem Chabang Port, during which the ROV was utilized to navigate a 300-m trajectory while consistently documenting velocity and power usage. Results show that as the tether length increases, vehicle speed consistently decreases while power usage increases, indicating the effect of tether-induced hydrodynamic drag. Specifically, the velocity declined from 0.6706 m/s at the start to approximately 0.5500 m/s at 300 m, while power consumption rose from 0.7414 kW to around 0.778 kW. Linear regression was utilized to quantify these patterns, yielding two empirical models: V(x) = 0.6706−0.0003x and P(x) = 0.7414+(8 × 10−5)x, with x representing the tether length in meters. The models gave coefficients of determination of R 2 = 0.5834 and R 2 = 0.5965, respectively. This research presents one of the first empirical frameworks derived from in-field experimental trials to quantify performance degradation due to tether drag, thereby providing practical tools for energy budgeting and motion forecasting of stationary underwater vehicles in real-time operational planning. Unlike prior works relying mainly on simulations or analytical models, our study delivers regression-based predictive equations validated across different test sites. This contribution not only enhances operational readiness but also establishes a solid foundation for future investigations into nonlinear modeling and the development of adaptive control systems that incorporate tether dynamics to further improve predictive accuracy. • Increasing tether length significantly reduces ROV speed in calm water tests. • Power consumption rises linearly with cable length due to hydrodynamic drag. • Empirical models predict speed and power trends based on tether length. • Results improve energy planning and mobility forecasting for tethered ROVs. • Findings support future development of tether-aware control algorithms.