OVERVIEW: CONTRALTO-S (SLAT) is an active, expendable torpedo decoy system designed for use aboard submarines. It provides soft-kill defense against incoming acoustic torpedoes by emitting deceptive acoustic signals to mislead and divert them.

DETAILS: CONTRALTO-S is the submarine version of the French Navy’s Soft-Kill Anti-Torpedo SLAT (Système de Lutte Anti-Torpille) system developed by Naval Group. It uses externally launched expendable effectors to generate broadband acoustic interference and deploys false targets across the full sonar frequency spectrum. Once deployed, the effectors emit high-intensity jamming signals and simulate submarine-like signatures to deceive torpedo seekers. The system is fully automated and designed to operate in high-threat environments without requiring operator input during engagement.

FUNCTION:
It is launched from submarine-mounted external decoy launchers.
Once deployed, it emits broadband active acoustic signals and releases mobile target simulators.
This creates multiple false sonar returns that confuse and seduce torpedoes away from the submarine.

Platforms: S 601 Rubis, S 605 Améthyste, S 616 Le Triomphant, and S 635 Suffren submarines of the French Navy.

SOURCE:
Naval Group: https://www.naval-group.com/en/news/naval-group-anti-torpedo-defence-system-proves-its-effectiveness ; Defense-Aerospace: https://www.defense-aerospace.com/dcns-torpedo-defense-system-passes-tests ; Naval Technology: https://www.naval-technology.com/projects/contralto/