Fin Stabilizer

A fin stabilizer is a fin projecting from a ship hull below the waterline that counters the rolling motion caused by wind and waves; an active fin stabilizer uses a gyroscope to sense the roll and adjusts the fin angle of attack so that the ship own forward motion generates a corrective force, working on the same lift-generating principle as an aircraft control surface, and it needs the ship to be moving above a minimum speed to be effective. The system was invented by Motora Shintaro working with Mitsubishi Shipbuilding in Japan, who patented the design in 1922, and a Japanese ocean liner first carried it into service in 1933. The British Royal Navy became an early major adopter, installing Denny-Brown fin stabilizers on more than a hundred warships by 1950, and the United States Navy followed with installations including USS Gyatt in 1956 and USS Bronstein in 1958.