USA As Represented by Secretary of the Navy

Christopher N Sears

William E Schneider

Frank B Peterson

Dana C Lynn

Donald Maxwell

Frank S Halliwell

Darrel J Brydebell

Adamandios G Gafos

Mark W Smith

An acoustic data acquisition system for shipboard use is disclosed that allows for underwater acoustic data measurements at preselected submerged marine structural coordinates using a free swimming, quiet dynamically positionable remotely operated vehicle (ROV). Moreover, the disclosure provides a method of performing acoustic data acquisition with an ROV by first inputting the marine structural features by use of a computer aided design subsystem, determining the required trajectory path and hovering coordinates for data measurements, next, establishing the acoustic telemetry system for the remotely operated vehicle's control system to operate within and make an absolute positional fix to the marine structure's coordinates then, establish the ambient acoustic conditions of the worksite. The system is monitored and controlled from a computer based system. The system includes an ROV subsystem that operates in conjunction with a computer based long baseline underwater telemetry and positioning control subsystem, an acoustic transducer array attached to the ROV and a real time data-coordinate storage subsystem. A particular type of transducer suitable for use with this vehicle is a passive acoustic transducer array (hydrophones) that measures low level sound pressures and phase data that provides a detailed description of the sound power field emitted over the surface of the marine structure. Applications include oil/gas pipeline leak detection and location of malfunctioning underwater marine equipment.

Underwater acoustic data acquisition system

An improved integral marine propulsion unit is disclosed that can generate a thrust vector in any of three degrees of motion. The unit utilizes both collective and cyclic propeller blade pitch angle variation to generate these thrust. This unit obviates the need for control surfaces and rudders for motion control of a marine vessel. Additionally, this unit provides flexibility in external propulsor arrangements on a marine hull. The unit integrates the swash plate mechanism and actuators within the central bore of a ring type prime mover.

Propeller unit with controlled cyclic and collective blade pitch

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Shady Side, MD, United States of America

Christopher N Sears