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Fat Line Towed Array Straightening System
Navy SBIR 2012.1 - Topic N121-074 NAVSEA - Mr. Dean Putnam - [email protected] Opens: December 12, 2011 - Closes: January 11, 2012 N121-074 TITLE: Fat Line Towed Array Straightening System TECHNOLOGY AREAS: Sensors ACQUISITION PROGRAM: PMS401 ACAT IV Programs: TB-16 Fat Line Towed Array and TB-34 Next Generation RESTRICTION ON PERFORMANCE BY FOREIGN CITIZENS (i.e., those holding non-U.S. Passports): This topic is "ITAR Restricted". The information and materials provided pursuant to or resulting from this topic are restricted under the International Traffic in Arms Regulations (ITAR), 22 CFR Parts 120 - 130, which control the export of defense-related material and services, including the export of sensitive technical data. Foreign Citizens may perform work under an award resulting from this topic only if they hold the "Permanent Resident Card", or are designated as "Protected Individuals" as defined by 8 U.S.C. 1324b(a)(3). If a proposal for this topic contains participation by a foreign citizen who is not in one of the above two categories, the proposal will be rejected. OBJECTIVE: The objective is to develop a system that would keep the Fat Line (TB-16 series and TB-34) arrays straight and horizontal while towed at speeds as low as 1.5 knots to improve array effectiveness and reduce damage in shallow waters. DESCRIPTION: Towed Fat Line arrays are being used in shallow water and with SSN/SSGN add-on systems like the Advanced SEAL Delivery System (ASDS) that require very slow (near hovering) towing speeds. Fat Line arrays are not effective at tow speeds below three (3) knots. At those tow speeds (and slower), the Fat Line array "droops" from front to back and also becomes less straight. These distorted spatial configurations (from both straight and horizontal) each reduce the array�s acoustic effectiveness. The Ship Safety/Self Protection that the Fat Line array would normally provide to the SSN/SSGN is greatly degraded. This degradation is especially exaggerated with the use of the newest Fat Line, the TB-34. This array has higher frequency capability which requires more precise knowledge of the individual sensor locations and renders it more susceptible to spatial distortions. Lastly, very slow speed towing can greatly contribute to the likelihood of damage by contact with the ocean bottom. Low speed front to back droop must be less than 20 feet and off-axis distortions (straightness) must be less than 1 foot per 10 feet of length. Examples of methods could include but not be limited to a drag inducing drogue, aft pulling propulsion system, active buoyancy control, and array hose wall stiffness adjustment using rheological fluids. Consideration should include the ability to transfer the straightening system from array to array versus being embedded into the array itself. There is significant innovation required to develop any of these concepts to the point where they become integrated with the Fat Line towed array and the submarine Fat Line stowage tube. The aft drogue or propulsion system must be stable at all speeds up to submarine flank, propulsion has to be powered by the host sonar through the array, and all concepts must fit within the SSN Fat Line Stowage Tube. In addition any active control needs to interface with the A-RCI host sonar suite and must use either legacy (to the array) sensors or provide proper sensors and data connection as part of the developed system. Concepts shall not impede high speed towing stability. PHASE I: Develop concepts for straightening Fat Line arrays and for removing front to back droop under low speed towing conditions. Demonstrate the feasibility of the concepts to straighten Fat Line arrays and to remove droop within the requirements described above. Demonstrate the feasibility of developing the technology to meet the Navy need. Feasibility calculations, modeling, and modest demonstrations should be used to identify optimum concepts for consideration under Phase II. Develop a Phase II development plan with performance goals and key technical milestones. PHASE II: Based on the results of Phase I and the Phase II development plan, develop a prototype system to straighten Fat Line towed arrays and to remove droop. Evaluate the prototype in a controlled environment to assess the ability of the system to meet performance requirements described above and the performance goals identified in Phase I. Based on the prototype evaluation, determine the refinements needed to produce a final full-scale system. Develop a Phase III development plan to transition the technology into a system that can be acquired by the Navy. PHASE III: If Phase II is successful, the small business will be expected to support the Navy in transitioning the technology to Navy use should a Phase III award be made. Based on the Phase II results, the contract will develop and incorporate the selected straightening system into an in-service array for shipboard testing and evaluation in the desired end-use environment. Continue technology development to support shipboard qualification tests and requirements. PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: Technology innovations under this topic could have commercial application in seismic oil or gas exploration systems. REFERENCES: 2. TB-16 Fat Line Towed Array: 3. Towed array spatial factors: KEYWORDS: Drag inducing drogue; aft pulling propulsion; active buoyancy control; rheological fluids; towed array droop; low speed towed arrays
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