Avoidance of Twinline Towed Array Entanglement

The Program Executive Office of the Littoral and Mine Warfare Systems (PMS 485) operates SURTASS TwinLine acoustic surveillance arrays in the Western Pacific where they encounter areas of intense fishing activity. The TwinLine array system consists of two acoustic streamers that are towed by a heavy tow cable and separated by mine-sweeping paravanes on short tethers that pull out and down. These paravanes provide the lateral force necessary to separate the streamers and also provide horizontal stability to maintain the planar TwinLine array geometry. The system is susceptible to entanglement by fishing gear which causes collapse of the tow system, a significant degradation in acoustic performance, and often damage to the tow system necessitating retrieval of the array and repairs. In response to SBIR solicitation 2004.3 N04-210, Applied Hydro-Acoustics Research, Inc. (AHA) describes in this proposal the work required in a Phase I effort to develop a prototype anti-fouling separation and roll control system to minimize the opportunity for entanglement in fishing lines and nets it encounters, and minimizes the impact of entanglement, thereby increasing operational availability and minimizing damage to TwinLine towed arrays.