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www.sea-technology.com December 2015 / st 37 F rom June 12 to July 27, 2014, as part of its ongoing commitment to integrity management of its sub- sea pipeline network and subsea assets in Australia, Quadrant Energy Australia Ltd. com- missioned UTEC Survey to conduct a survey of these pipelines using a low-logistics AUV. This was deployed from a vessel of op- portunity, with a key objective of following the pipelines along their en- tire length, including the nearshore sec- tions of the pipelines as they approach Vara- nus Island and the Australian mainland. The use of AUVs over traditional survey methods has several advantages. The ones most apparent in this survey were the consistently high-quality data, the ability to operate in very shallow waters, and the lower cost. UTEC, which owns and operates the largest feet of Tele- dyne Gavia AUV systems in the world, externally examined 20 survey platforms, as well as 43 pipeline routes and ad- jacent seabed, to determine their present condition and po- sition. Features such as pipeline supports, freespans, rock pinnacles, anchor scars, and debris adjacent or in contact with the pipeline were identifed. The MV Yardie Creek, a 35-m multipurpose vessel op- erated by Arrow Pearl Co. of Broome, Australia, was used as the vessel of operations for this project. A rigid hull in- fatable boat (RHIB) was used for AUV launch and recov- ery operations, as well as nearshore work. AUV recovery involved manually lifting the AUV into the RHIB, placing it in custom-made chocks on the deck to avoid shock damage to the modules, and then hoisting the AUV from the RHIB to the deck of the vessel using the vessel's HIAB crane. Teledyne Gavia AUVs Two UTEC-owned Teledyne Gavia Commercial Surveyor AUV systems were used in the project, depth rated at 2 to 1,000 m. The modular design of the system allows for dif- ferent sensors to be installed based on the needs of the sur- vey. The confguration used on this project gave the AUV an approximate length of 3.5 m and weight of 120 kg. The system was powered by two lithium-ion battery modules. The battery duration was largely dependent on the active sensors and the speed of the AUV. The confguration used here allowed for a running time of 5 to 6 hr. at a survey speed of 3.5 to 4 kt. The AUV positioning solution was achieved using a com- bination of differential GPS (DGPS) and an INS aided by a DVL. DGPS corrections were pushed to the AUV GPS sys- tem via Wi-Fi from the vessel of operations. This ensured that the AUV had an extremely accurate position before div- ing and losing GPS reception. After the AUV left the surface, a combination INS/DVL system took over navigation by cal- culating the AUV's positon. AUV mission planning and control was achieved using a combination of two pieces of software. AUVView, a product of 4D Nav, was used for mission planning prior to the start of the project. AUVView allowed for executable mission plans to be generated on top of client-provided drawing fles, then exported into the Teledyne Gavia control soft- Low-Logistics AUV Pipeline Inspection Acquiring High-Resolution Geophysical Data in Very Shallow Water By Bryan M. Keller • Travis Hamilton • Simon Hird h a T Example of AUV GeoSwath data depicting spud can depressions.