The Magazine for Underwater Professionals
EdgeTech, USA, reports its AUV-based sidescan sonar system played a key role in the recent discovery of the USS Indianapolis wreckage 5.5 kilometres deep in the Philippine Sea. The sinking of the USS Indianapolis had the greatest loss of life from a single ship in the history of the US Navy.
The wreckage was discovered on 18 August by the expedition crew of the research vessel Petrel, which is owned by Microsoft co-founder and philanthropist Paul Allen, after new research from a naval historian pointed them to a specific region of the ocean where the warship had been sighted the night before its destruction.
“The EdgeTech 2205 AUV-based sonar system is one of the many advanced underwater technology systems onboard the research vessel Petrel,” a spokesman told UCi. “The system is integrated into a deepwater AUV and is used on the vehicle to acoustically image large swathes of the seafloor as the AUV swims thousands of metres below the surface.”
The spokesman said the EdgeTech system is configured as a dual-frequency 75kHz/ 230kHz sidescan sonar and bathymetry providing the ability to image over 1000 metres from each side of the AUV as it conducts its search pattern in deep waters.
He added: “EdgeTech takes great pride in providing high quality and, more importantly, reliable underwater acoustic imaging systems that are utilised by organisations and individuals such as Paul Allen and the research vessel Petrel. The company’s sidescan sonars, bathymetry systems and sub-bottom profilers are used daily throughout the world in modern research and military operations. This discovery highlights the important role the technology can also play in the historical understanding and recognition of past military operations.”
Planet Ocean, UK, and ASV Global, UK, have demonstrated the autonomous launch and recovery of multiple AUVs from an autonomous surface vehicle as part of their Innovate UK project.
The demonstration took place in the Solent and was carried out in front of invited guests from project partners the National Oceanography Centre (NOC), UK, and the University of Southampton, UK, and funders Innovate UK and the UK Defence Science and Technology Laboratory (Dstl).
“The day marked the final activity of the highly successful two-year Innovate UK project, during which two extremely capable, low cost AUVs were developed along with the launch and recovery systems which can be installed on almost any floating asset,” said a spokesman.
The technology has also contributed to a University of Southampton project which has been air-launching ecoSUBµ AUVs from the university’s SPOTTER unmanned air vehicle.
During the demonstration, ecoSUBµ AUVs were launched autonomously from three launch tubes mounted on the stern of an ASV C-Worker-5 unmanned surface vessel.
“Missions can be sent to the AUVs whilst in their launch tubes via the C-Worker communications, after which the system can operate autonomously. The C-Worker can then act as a communications hub downloading high-resolution data from the ecoSUBµ for storage or onward transmission through high bandwidth channels before collecting the AUVs using a specially designed recovery system modelled on a Jason’s cradle,” explained the spokesman.
A universal interface to facilitate AUV docking with subsea structures is being developed through international collaboration between companies and universities in Brazil, Norway, Poland, Sweden and the UK.
The consortium, led by Norway-based WiSub, includes Bergen University, Norway, DOF Subsea, Norway, easySubsea, Brazil, the Federal University of Rio de Janeiro, Brazil, Kongsberg Maritime, Norway, Saab Dynamics, Sweden, Sonardyne, UK, Statoil, Norway, Swire Seabed, Norway, and the Warsaw University of Technology, Poland.
A spokesman said: “Statoil is driving the initiative in a project whose results shall enable long-term remote operation of underwater vehicles through battery charging and high-bandwidth data transfer via a seabed-based docking station. The ability to charge distributed sensor networks from AUV systems shall also become possible with bi-directional power transfer being developed in the project.”
The joint industry project is receiving financial support from the Research Council of Norway and Brazil’s R&D funding body Finep. The project is led in Norway by WiSub and in Brazil by easySubsea, specialists in pinless power and data connections and wireless underwater communication respectively.
“Battery life of seabed-based robotics typically does not extend beyond a day or two before requiring recharge,” said the spokesman. “The vast amounts of data collected by an AUV also requires distribution and processing, typically to an onshore facility for analysis.”
He continued: “Connection to an underwater cabled network linking seabed to shore is the primary means to achieve charging and data transfer, however connection systems that employ conductive pins have tight mating tolerances, sealing systems and limited mating cycles. By removing the pins from connections, repeatable reliable underwater connection and disconnection becomes an achievable reality.”