Sea Technology

MAR 2014

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

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Page 15 of 75

16 st / March 2014 cated the frst phase of the project to developing a numeric simulation tool to evaluate in time and space the ca- pability of harvesting solar and wind energy. In order to further understand these challenges, a representative cata- maran ftted with a solar panel, wind generator and data logger was moored in realistic conditions for a month to study the performance of these devices and evaluate the software predictions. The team also completed a full-scale towing test to validate their hull drag CFD simulations. The experiments and simulations indicated that a large so- lar array (10 square meters) coupled to a wind generator and a micro-diesel generator would reliably provide the required energy. ASV worked with Hyperdrive to design and build the electrical sys- tem. The components were extensively bench tested in order to optimize the power management system and the cooling system and identify possible points of failure. Hyperdrive's expertise in the design and build of electric cars was vital to the success of the project. The enclosed volume of the mast and the 2-meter-long pivoting keel ensure the catamaran platform is very stable and capable of self-righting, al- lowing operation in harsh weather conditions. In order to save weight and assure a stiff and rugged structure, the designers selected a hybrid carbon- fber Kevlar prepreg construction. Even when fully loaded, the unit is still eas- ily recoverable using a small trailer on a slipway or vessel crane/A-frame. The high-effciency propulsion sys- tem in combination with the optimized wave piercing hull form, low-power electronics and a bespoke battery bank allow the system to provide up to 100 watts continuous or 500-watt bursts of power to payloads weighing up to 25 kilograms. A variety of sensors can be mounted on the mast, under the deck and on the retractable keel. In addition to this, the vehicle can be ftted with towed underwater instruments. The ve- hicle's fexible energy and propulsion system cater to the additional drag. Reliability was a key design driver for the system. In order to minimize the number of moving parts, the steering system relies on the differential thrust of a pair of precise, controllable, high- quality, synchronous motors. ASV used its experience in the design and build of military-spec vessels to maximize ruggedness and only selected high- quality materials and components. Command and control algorithms were developed to ensure the vehicle maximizes the effciency of its energy generation and consumption. The al- gorithms incorporate wind, ocean cur- rent data and a model of the vessel's performance over a range of different conditions. Working alongside Cranfeld Uni- versity, which has considerable experi- ence in collision avoidance algorithms, ASV developed a code that utilizes AIS (automatic identifcation system) and a near-feld radar to avoid other vessels and foating objects. ASV used their highly developed command and control system AS- View, which has been deployed on more than 40 different unmanned marine systems. This system can be operated using a variety of communi- cation technologies, including WiFi, UHF and L-band line-of-sight radio systems, and Iridium, Inmarsat and V- Sat satellite systems. ASView can be set to automatically change the com- munication method depending on the best available bandwidth, for example, automatically shifting between line-of- sight radio communications and over- the-horizon satellite communications when required. Sea Trials For the initial sea trials and dem- onstrations, an Airmar (Milford, New 8 cm accuracy worldwide (2drms) High accuracy Heading/Pitch and Roll sensors GPS, GLONASS and GNSS solutions QA/QC NMEA outputs compliant with OGP 373-19 / IMCA S 015 Precise Stable & Reliable Easy to install Angola Brazil Mexico Singapore South Africa United Kingdom USA Positioning - for success. "Command and control algorithms were developed to ensure the vehicle maximizes the effciency of its energy generation and consumption." MarBook.indd 16 3/10/14 2:12 PM

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