Towed, winged vehicles are often used for purposeful surveying from research vessels. Scripps has been operating the vehicle SeaSoar since the mid-1990’s. SeaSoar is controlled by adjusting the angle of attack of pivoting wings, which causes it to fly typically in a sawtooth pattern from the surface to 300–400-m depth at a tow speed of 4 m/s. With a cycle taking about 12–15 minutes, a horizontal resolution of about 3 km is achieved. As SeaSoar is towed on a conducting cable, data are communicated in real time. Wing control is active, so SeaSoar can be programmed to follow pressure or density surfaces, allowing horizontal resolution as fine as 4 m. The SeaSoar vehicle has a substantial payload, and all manner of sensors have been deployed successfully. SeaSoar has been used in a variety of applications, including three-dimensional surveys of specific mesoscale features, and long sections to quantify statistical properties of horizontal hydrographic structure.

Figure 1. SeaSoar on the deck of the R/V Revelle, The wings are upside-down relative to an aircraft, as downward lift is required for the SeaSoar to dive.

Acknowledgements. SeaSoar operations have been supported by the Office of Naval Research and the National Science Foundation.