Temperature boundaries refract sound and can shelter a submarine from sensors above the layer, so sonobuoys may suspend hydrophones at selected depths. Multiple layers and imperfect knowledge of their positions prevent the search from becoming mechanical. Ocean and weather models can identify water behaving unexpectedly, but they still leave aircraft to distinguish a submarine from whales, fish, wrecks, and other causes. Extra-large uncrewed underwater vehicles (XLUUVs) could imitate a contact and draw investigators away from the real boats. An air-dropped torpedo therefore signals unusually high confidence and forces the submarine to evade, hide, or run.
Chapter · 44:13-47:02
Sonobuoys pierce thermal layers; torpedoes force decisions
Understand how thermal layers complicate sonar, how suspended sensors listen below them, and why an air-dropped torpedo transforms the hunt.