OVERVIEW: The BT-4 is a 115 mm caliber, ship-launched, unguided chaff decoy designed for radar deception against anti-ship missile threats. It is used to disperse radar-reflective material that creates false targets to confuse and mislead enemy radar systems.

DETAILS: The BT-4 is a naval chaff round developed in Israel and designed to be launched from 115 mm deck-mounted decoy launchers. It contains radar-reflective fibers that, once dispersed, generate a radar cross-section larger than the ship itself, masking the vessel’s position or generating multiple false returns. The round is optimized for close-in defense against incoming radar-guided missile threats and functions by rapidly forming a radar-reflective cloud in the threat’s path.

– BT-4’s Function:
It is launched from a ship-mounted 115 mm decoy dispenser.
Once deployed, it disperses radar-reflective chaff material into the air to generate large radar signatures that obscure the ship’s location.
This creates a deceptive radar return, fooling enemy missile seekers or targeting radars into tracking the chaff cloud instead of the vessel.

Platforms: Israeli Navy Sa’ar-class missile boats and corvettes.

SOURCE:
Rafael Advanced Defense Systems: https://www.rafael.co.il/worlds/naval-warfare/naval-self-protection/ ; Israel Ministry of Defense Exports Catalog ; Jane’s Naval Weapon Systems ; GlobalSecurity.org: https://www.globalsecurity.org/military/world/israel/navy.htm