Francis, H. and Traykovski, P., . Development of a highly portable unmanned surface vehicle for surf zone bathymetric surveying.
This study reviews the design and subsequent effectiveness of a prototype autonomous survey vehicle built to collect data specifically in the surf zone. The breaking wave transitional zone between ocean and land is an important location to survey due to its impact on human infrastructure and vulnerability to the effects of climate change. However, this environment is notoriously difficult to survey due to its shallow depth and the turbulence of waves and currents. Three distinctive design choices were made at the beginning of the project with the goal of operating in the surf zone: First, the surface vehicle is light (15 kg) and fast (up to 7 m/s), both characteristics intended to enable one person to deploy it quickly and easily into the surf zone. Second, an electric motor that is connected to a jet drive eliminates a combustion engine's air intake, which can be contaminated with seawater and sand. The jet drive also removes any danger of spinning propellers and allows the vessel to run in very shallow water. Finally, the vessel has a foam bulb hatch cover that is watertight and allows the vessel to right itself if capsized by a wave. The outcome of this development effort is an unmanned vessel that has the maneuverability and power sufficient for surf zone operations and is self-righting. It runs off the waypoint based Ardupilot Mavlink program, which allows rapid transitions from autonomous modes to remote controlled modes and has a runtime of approximately 1.5 hours. The vessel has initially been used with a single beam echosounder and precision GPS to create highly detailed shallow water bathymetric maps. This study demonstrates this technique as a highly efficient method of creating bathymetric maps in coastal environments.