The marine environment presents a complex challenge for unexploded ordnance (UXO) search technologies because it includes wetlands, freshwater ponds and lakes, estuaries, rivers, coastal bays, tidal flats, and ocean shores, including coral reefs in shallow water.

The objectives of this project were to acquire the components to build an underwater UXO search system, test and integrate the components, complete the full system integration and shakedown testing, and conduct several UXO demonstration surveys.

Technology Description

Much of the modeling and engineering design work was completed through an earlier SERDP project, Technology Needs for Underwater UXO Search and Discrimination (MR-1322). This ESTCP project built on the previous work and proceeded to develop and demonstrate a field-worthy prototype of the marine towed array UXO sensor system. This platform, with nominally 4-meter wide sensor arrays, is designed as an underwater flying wing. It is towed by a 20-meter cable attached to a 30-foot long triple pontoon boat. The maximum design operational speed is 5 kt. Assuming the system is used to survey 4 m wide lanes at 5 kt, the survey production rate is 3.7+ hectares/hour, or slightly less than 10 acres/hour. This does not count the time spent in turns or in raising or lowering the platform. The Global Positioning System (GPS) location and navigation system, the data acquisition system, the pilot guidance system, and physics-based data analysis system all draw heavily on developments in the ESTCP project entitled Airborne UXO Surveys Using Magnetometer Arrays (MR-200031).

Demonstration Results

The marine towed array (MTA) system was first demonstrated in the Currituck Sound adjacent to the Former Duck Bombing Range near Duck, NC in late 2005. The second demonstration took place in Ostrich Bay (Puget Sound, WA) adjacent to the Former Naval Ammunition Depot Puget Sound. Additional system demonstrations were conducted at increasingly challenging sites. In part, these demonstrations were intended to explore and expand the operating conditions of the MTA system under more challenging site conditions. The sites include the Lake Erie at the Former Erie Army Depot, OH; Bahia Salinas del Sur Vieques, Puerto Rico; and the Blossom Point Research Facility, MD. The MTA successfully characterized munitions contamination at these sites and the system design and deployment techniques were refined.

Implementation Issues

The MTA has successfully transitioned into the community and is currently being used in operational munitions response projects.