Dynamics of a wave propelled surface vessel

ASVs have proven effective as ocean observing platforms for maritime operations. Despite the potential impact for sustained long-term ocean monitoring, current autonomous platforms are limited in their operation requiring periodic recharging (and redeployment) from a support vessel. This project aims to establish the fundamental principles of a submerged tandem flapping foil mechanism to convert ocean wave energy directly into propulsion for ASVs, eliminating the necessity to carry sufficient propulsive energy reserves for entire missions. This research seeks to understand the relationships between the motions, energy and forward speed of a surface vehicle with submerged flapping foils. Following an initial study in regular head and following waves, and observed in situ by the CASE partner, the response of an ASV with submerged flapping foils is particularly sensitive to the wave conditions and design parameters, with varying individual foil contributions and a significant oscillatory forward speed. However, in practice assumptions of regular, linear waves are limited and rarely the case. This research aims to identify the theoretical performance limits, key design parameters and approaches to control the forward speed in irregular and oblique sea-states. With scientific ship time measured in the tens of thousands GBP per day, operating costs around $5M p.a. (maintenance and crew) and research vessel costs between $50-200M, this research will lead to significant cost savings and measurements on ever larger temporal and spatial scales - a step change in maritime robotic capability.