Roll angle is often a limiting factor during high-speed turns and repetitive turning maneuvers. Navy and Coast Guard surface ships are designed for high-speed operation. Sharper turns at higher speeds, and repetitive high-speed turns can increase ship survivability by helping these vessels avoid incoming threats. This is particularly true if the amount and direction of roll during the turn is controlled, since the ship's susceptibility to radar and other sensors may be diminished at certain angles. Sharper turns at higher speeds can also reduce the time it takes to reach a person in the water, improving the chances for successful rescue. Controlled roll during repetitive sharp turns can make high-speed pursuit safer and more likely to succeed. The objective of this thesis is to study the effects of fin stabilizers on a ship's turning performance. Fin stabilizers, commonly added to a ship design for the sole purpose of minimizing unwanted roll during ordinary operations, are shown to also favorably influence both the magnitude and direction of heel experienced during high speed and repetitive maneuvers. The effects of fin stabilizers on other turn performance characteristics are also examined. A strategy for actively employing fins during maneuvers is proposed.

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http://archive.org/details/finstabilizerssm109456145

Lieutenant Commander, United States Coast Guard