Dynamic Compensation System for Towed Bodies

The use of unmanned surface vessels (USV) towing underwater sensors will be part of the Littoral Combat Ship concept of operations for mine, anti-submarine, and anti-surface ship warfare. However, the wave-induced motions of the USV may degrade or limit sensor performance unless measures are taken to decouple the tow body motions from the USV motions. Given limitations on available USV power and the desire to implement robust, automated deployment and retrieval of the tow body from the USV, the existing approach of using an intermediate semi-submersible tow body to limit motions is not desired for this application. Applied Physical Sciences Corporation (APS) proposes to develop the preliminary design of a novel sheave concept to provide tuned passive motion compensation while simultaneously permitting automated tow body handling. During Phase I, APS will develop a physics-based simulation tool by combining an existing three-dimensional seakeeping tool, AEGIR, and an existing non-linear cable model to provide coupled simulations of the USV-cable-tow body system dynamics. The coupled simulation tool will be used to design and optimize the performance as well as to develop a preliminary concept of operation of the proposed concept in conditions up through Sea State 4.