OVERVIEW: The Anti-Torpedo Torpedo (ATT), also known as Countermeasure Anti-Torpedo (CAT), is a lightweight, hard-kill torpedo interceptor developed for close-in defense against incoming torpedoes. It was introduced in 2019 by the United States Navy under the Surface Ship Torpedo Defense (SSTD) program.

DETAILS: The ATT/CAT system was developed by the U.S. Naval Undersea Warfare Center in collaboration with key defense contractors as part of an active torpedo defense initiative. The system uses a very small, high-speed torpedo designed to detect, track, and destroy incoming torpedoes before they reach the host platform. Deployed in conjunction with sensors and processing units like the AN/SLQ-61 Lightweight Tow (LWT) Array, the CAT is launched from an onboard anti-torpedo defensive suite. While originally intended for aircraft carriers and select high-value units, the program was eventually paused after limited deployment.

TYPE: Lightweight anti-torpedo interceptor

FUNCTION: Once launched from the host ship, the ATT/CAT uses onboard sonar and tracking algorithms to acquire the incoming torpedo. It then intercepts and destroys the threat via direct impact or proximity detonation before it can reach the defending vessel.

NOTE:
IOC: 2019 (limited operational capability)
Operators: United States (limited trials)
Platforms: USS Gerald R. Ford (CVN-78, initial integration), other Nimitz-class carriers (testing phase)
Conflict used in: No confirmed combat use
Manufacturer: U.S. Naval Undersea Warfare Center (NUWC), with industry support (e.g., Northrop Grumman, Ultra Electronics)

SOURCE:
U.S. Navy NAVSEA: https://www.navsea.navy.mil ; Federation of American Scientists (FAS): https://fas.org/man/dod-101/sys/ship/weaps/index.html ; GAO Defense Systems Reports ; Naval Sea Systems Command Briefings ; SIPRI Arms Transfers Database: https://armstrade.sipri.org