Sea Technology

DEC 2012

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Korea Institute of Ocean Science and Technology. Two gliders were purchased by the Korea Institute of Ocean Science and Technology, formerly known as the Korea Ocean Research and Development Institute, in 2010 and 2011. Each was equipped with four omnidirectional acoustic sensors: one mounted on the nose cone, one on the top of the vertical stabilizer and one on each wing tip. Two tests were conducted with LG19 in 2011 off the east coast of Korea. The frst test consisted of fying the glider 112 kilometers from the coast of mainland Korea to Ulung Island. Due to currents expected to be in excess of 1 knot, an average speed of 1.5 knots was commanded. As expected, the glider was carried north of the projected path and spent much of the time ferrying against the current, resulting in a speed over ground signifcantly less than the commanded speed. After six days, the glider arrived at the island, but recovery was delayed due to weather, which did not clear until after the battery was depleted and contact with the glider was lost. Three months later, the glider was recovered in fshing net and returned undamaged to the institute. In a second outing, the glider encountered lower currents, with an average commanded speed of 1.2 knots. The glider arrived at the island after two days and with substantial battery reserves. The glider was then fown back to the mainland via a series of heading commands, without attempting to follow the waypoint tracks. The institute is planning additional tests. University of Southern Mississippi. The University of Southern Mississippi has supplied a JFE Advantech Co. Ltd. (Kobe, Japan) RINKO II dissolved oxygen sensor and a Wetlabs ECO FLNTU (Philomath, Oregon) combined turbidity and fuorescence sensor for integration onto a glider platform. The vehicle will study hypoxia in the Gulf of Mexico. The sensors have been integrated on LG18, and testing is scheduled to verify the ability of the glider to operate in the shallow gulf waters near the coast in November 2012. Testing was scheduled for water depths from 10 to 30 meters. If the glider operates well, it will be fown into shallower water to determine minimum operational depths. Future Developments A program has been started in conjunction with the University of Alaska Fairbanks to modify the glider communications system to provide subsampled science data to the user via an Iridium RUDICS (Router-Based Unrestricted Digital Interworking Connectivity Solutions) pathway. In addition, an emergency lift bag system, powered by CO2 cartridges, has been developed and was used on the glider during initial testing. This system was designed for temporary use and is not currently available to customers due to usability and reliability issues. A redesign to eliminate these shortcomings and include the emergency lift system as a standard system component is underway. Sea & Sun Technology Acknowledgments The authors would like to thank Dr. Mike Traweek from ONR for his continued support of the glider development. Original funding for the glider program was provided by ONR under contract N00014-07-C-0834. Followon funding was provided under contract N00014-11-M-0069. The authors would also like to thank David Trivett and James Martin of Georgia Tech, Dr. Kevin Smith and Tad Masek of the Navy Postgraduate School, Mr. Nathan Banks of the Naval Undersea Warfare Center, Dr. Yossup Park of the Korea Institute of Ocean Science and Technology, Dr. Vernon Asper and Kevin Martin of the University of Southern Mississippi, and Dr. Peter Winsor of the University of Alaska Fairbanks for their support and willingness to share operational plans and information regarding the gliders. References For a list of references, contact Ray Mahr at ray@exocetus.com. n Ray Mahr. Jr. is the co-founder of Exocetus Development LLC. He has extensive experience in the design, development and sales of instrumentation and equipment systems for oceanographic and underwater acoustics applications. As a former senior manager at three oceanographic instrumentation companies, he directed implementation of new oceanographic products and systems. Joe Imlach was the chief mechanical engineer at ANT LLC and served as the principal investigator and program manager on the Littoral Glider project. He subsequently formed Exocetus Development LLC, which purchased the rights to the Littoral Glider product from ANT. He is currently president and chief technology offcer of Exocetus. www.sea-technology.com DECEMBER 2012 / st 39

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