OVERVIEW: The Mk 59 Mod 0 is a 197 mm (approximately 10‑inch) floating radio‑frequency (RF) decoy system introduced in 2014. It is designed as a passive off‑board corner‑reflector decoy to mimic a ship’s radar signature and seduce RF-guided anti-ship missiles.

DETAILS: The system is a compact, inflatable octahedral decoy launched from deck-mounted tubes without requiring shipboard power. Once inflated, it floats behind the vessel and produces a radar cross-section (RCS) comparable to that of a small ship. It was initially adopted by the Royal Navy (as IDS300) and later by the U.S. Navy under the designation Mk 59 Mod 0, with deployment on Arleigh Burke-class destroyers beginning in late 2013–2014. The decoy supports multiple roles- seduction, distraction, confusion—by generating a consistent, autonomous reflector signature over its sea surface.

FONCTION:
Fired from deck-mounted floating decoy tubes.
Inflates to deploy a high-RCS octahedral structure on the water surface.
Drifts behind the ship to lure RF-guided missiles away from the vessel.

SOURCE:
Wikipedia – “Naval Decoy IDS300” ; Free Library – “Naval Soft-Kill Technologies” PDF ; Jane’s Naval Decoy IDS300 article ; ThinkDefence – “Floating Decoy System FDS3” overview