Periodically, a submarine will perform a maneuver called clearing baffles, in which the boat will turn left or right far enough to listen with the forward array sonar for a few minutes in the area that was previously blocked by the baffles. Good tactics require a submarine to clear baffles at irregular intervals and in different directions so that a pursuing submarine cannot predict when and how the next baffle-clearing maneuver will be made. When a submarine clears its baffles, a pursuing submarine must take measures to avoid detection by, or worse, collision with, the submarine ahead. In some cases, submarine commanders could choose to clear baffles by executing one or a series of hard turns in order to not only clear the baffles, but also be in a favorable position to attack the potentially following submarine. Such extreme maneuvers were more commonly used by Soviet Navy submarines during the Cold War than by other forces, leading to the maneuver's nickname: "Crazy Ivan". The "crazy" came from the danger such a maneuver posed to both submarines, first being detection of the following submarine, which was commonly avoided by stopping the engines and going to maximum silence, and secondly by collision, as the momentum of the pursuing boat could result in collision with the leading submarine. The sudden, unexpected nature of the maneuver led to the term being used in the English-speaking world. The term Crazy Ivan has sometimes separately been used to describe the possibility of a rogue Soviet leader committing to military action, typically in reference to a limited launch of ICBMs against the US, originating from the Tom Clancy novel The Hunt for Red October. Angles and Dangles Although not specifically a baffle-clearing maneuver, the exercise known as "Angles and Dangles" (a series of random figure eights, sharp turns, and depth changes) is intended to eliminate the unintended self-noise which could occur during a baffle-clearing event. The exercise is executed at the start of a voyage to determine if loose items aboard the submarine are properly rigged for sea; loose items can fall or shift position during the sudden maneuvers required during baffle clearing, making noise that could be detected by the opposing submarine. Use of towed array sonars Most present-day submarines and ships carry a towed array sonar: a sonar sensor mounted on a long tow cable streamed out behind the vessel. This detects acoustic energy in