The trials were conducted in Dabob Bay, Washington, in May 1998. The main objective of these trials was to determine an accurate and reliable system to track a fishing trawl. Three USBL vendors were invited and agreed to participate in the trials. Nautronix Ltd. (Nautronix) provided their ATS II system, Simrad Subsea A/S (Simrad) provided their ITI system, and Ocean Research Equipment, Inc. (ORE) submitted their Trackpoint II Plus system. A local ORE distributor, MECCO, Inc. (MECCO), provided and operated the Trackpoint II Plus system. The U.S. Navy?s fixed, underwater tracking range in Dabob Bay, operated by the Naval Undersea Warfare Center (NUWC) Division ? Keyport, Washington, was also used in these trials. The range was used to provide simultaneous sub-sea positioning of the fishing trawl and to serve as a benchmark for system evaluations. The U.S. Navy also provided surface navigation support for the fishing vessel during these trials. The vessel selected by AFSC to conduct these trawls was the F/V Vesteraalen. It is 124 feet long, has a beam of 32 feet, and a draft of 18 feet. The F/V VESTERAALEN has a single, fixed-pitch propeller with a nozzle. By design, the vessel is like most in-shore trawlers and has, in fact, operated in Alaska in the past. The tests were conducted using NMFS otter trawls, typically used in Alaskan waters. A trial schedule was developed that would provide each vendor with three days to mobilize and test their systems. Each vendor?s equipment was attached to the fishing trawl, along with the U.S. Navy tracking gear. Both the U.S. Navy and the USBL vendor collected simultaneous trawl position data as determined by their respective equipment, with the trawl being dragged on the bottom along a predetermined track. The main objective of these trials was to assess the accuracy of each vendor?s equipment. This was accomplished using a statistical comparison between each vendor?s data and the U.S. Navy?s data that were observed simultaneously. This report details the results of these trials and summarizes the comparison results. It also contains details of the equipment and the methodologies used to collect and analyze the data. As a result of the data analysis, conclusions were drawn and recommendations have been included in this report.