baffels

The baffles is the area in the water directly behind a submarine or ship through which a hull-mounted sonar cannot hear. This blind spot is caused by the need to insulate the sonar array, commonly mounted near the bow, from the noise of the vessel's machinery.
During the Cold War, one submarine would frequently attempt to follow another by hiding in its baffles. This led to the practice of "clearing the baffles", that is, turning to observe the blind spot and detect any followers. Related maneuvers included the "Crazy Ivan", a hard turn to clear the baffles and position the submarine to attack any followers, and "Angles and Dangles", a five-hour process of rapid direction and speed changes to ensure that all items aboard were properly secured for hard maneuvering and would not fall or shift suddenly, producing noise that the enemy could detect. The baffles-clearing maneuvers undertaken by Soviet Yankee-class submarines were dubbed "Yankee Doodles."Hiding in a sub's baffles is dangerous because of the risk of collision. Such tactics have fallen out of use since the advent of the towed-array sonar, which negates the baffles' blind spot.

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