Unmanned Systems Technology 026 I Tecdron TC800-FF I Propellers I USVs I AUVSI 2019 part 1 I Robby Moto UAVE I Singular Aircraft FlyOx I Teledyne SeaRaptor I Simulation & Testing I Ocean Business 2019 report

44 F or a long time, the design of USVs has been geared towards conducting hydrographic and topographic surveys for various industries. Partly as a result of this, the development of unmanned watercraft these days is influenced less by boat manufacturers and more by the hydrographic surveyors who operate them. And just as UAVs need to minimise vibrations to avoid generating blurry imagery, so USVs must cope with being buffeted by waves or other boats if they are to generate actionable survey data. The shapes and capabilities of the vessels are therefore being designed more and more around stability and controlled manoeuvrability in a range of weather and maritime traffic conditions. Even in applications outside surveying, USVs are being built to hold their position and be resilient to external sources of motion or damage. Coastal surveys Florida-based Sea Robotics is close to completing the prototype of its newest platform, the battery-powered SR- Surveyor M1.8, which was unveiled publicly in April 2019 after about eight months of development. Although the company’s USVs have typically been larger than the new craft, which measures 1.83 x 0.91 m, Sea Robotics’ engineers sought to scale down its technologies and competencies to suit this vessel. “We’ve identified an increasing demand for man-portable bathymetry units that can operate in shallow waters or remote areas,” says Geoff Douglass, the company’s development manager for USV platforms. “To support multi-beam echo sounders on a vessel which can provide around a day’s worth of endurance, boats usually have to be much larger than the M1.8, in order to support the right battery capacity or fuel weight. Our next-smallest vessels are 2.5 to 3 m long, going up to 7 m long in our production series.” The M1.8 has a catamaran shape to provide additional stability and station- USV developers are ditching hull-like designs in favour of those that can remain more stable in a range of weather conditions. Rory Jackson reports The tide is turning June/July 2019 | Unmanned Systems Technology