SBIR-STTR Award

The ability to control the depth of submarine towed arrays is a tactically desirable capability needed to place the array in the optimum acoustic layer. Discounting submarine maneuvers, there are three basic ways to implement array depth control: control array buoyancy, control tow cable catenary shape (via cable density variations and/or properly oriented lateral force devices), and/or fly the array via a depressor or winged appendages. The Phase I effort will consist of conceptual design and analysis of the two most feasible approaches: 1) controlling cable density, and 2) flyable approach, emphasizing the anticipated towing profile, practical limitations for typical fleet operations, cable termination designs, system reliability, low cost, and manufacturability of each. An overall performance and relative cost matrix will be developed that will identify the best near-term and long-term design approaches. The immediate near-term solution proposed for shallow water operations is a variable density cable consisting of a lightweight (LW) section near the array, preceded by a heavyweight (HW) section. The long-term "flyable" solution proposed uses the aforementioned LW cable to tow the array, which will include deployable, winged lifting surface devices with active controls yielding a completely flyable system with absolute +/- depth control.

Benefit:
The anticipated benefits are three-fold: 1) the fleet will get an immediate near-term solution to enable safely towing the TB-16 array in shallow water, 2) a long-term solution that enables complete depth control of the array will also be identified that capitalizes on the aforementioned shallow water light weight tow cable design, and 3) array active depth control capability has applicability to the seismic oil exploration industry, and is therefore a "dual-use" technology.

Keywords:
Towed Seismic StreamerVariable Density Tow Cable, Depressor-Towed ArraySeismic Depth Control Birds, Towed Array Depth ControlShallow Water Capabilities

The Phase II effort will consist of parallel development of the HW/LW tow cable and the Dragonfly Depth Control System, identified during Phase I. The 1st year will develop the critical items needed to achieve the desired cable SG and demonstrate the variable density continuous extrusion process. For the Dragonfly system, the critical items are developing the wing and demonstrating its hydrodynamic performance, developing the wing fuselage test bed control system, and then installing and testing the components into the Dragonfly test bed module. The 2nd year will emphasize integrating the HW and VLW tow cables segments into a continuous-length strength member tow cable, performing PVT tests, and delivering a full-length pre-production HW/VLW tow cable to the Navy. For the Dragonfly system, the 2nd year will emphasize installing and testing the Dragonfly wet-end system in a prototype fuselage, testing the dry-end wing control system, and culminates with towing test of the prototype system. The 6-month Option Phase will emphasize final documentation of the HW/VLW tow cable qualification tests, including developing a Source Control Document, and Dragonfly systems integration tests with the TB-16 towed array system, culminating with delivery of the Dragonfly prototype system to the Navy for their evaluation.

Benefit:
The anticipated benefits are that the host platform will be able to operate in shallow water with a fully functional towed array system, thereby maintaining the current acoustic advantage over adversaries. The entire HW/LW tow cable would be deployed in deep water and also allow full acoustic capabilities. In shallow water, the heavy weight portion would be retrieved and only the LW portion would remain deployed. If further reductions in array depth are needed, then the Dragonfly lifting surfaces would be deployed, and the array system depth would be reduced even further. This combination of deep water and shallow water capabilities would be unmatched by any Navy.

Keywords:
Depressor-Towed Array, Towed Seismic Streamer, Shallow Water Capabilities, Variable Density Tow Cable, Seismic Depth Control Birds, Towed Array Depth Control