OVERVIEW: The Mk 46 Lightweight Torpedo Mod 2 is a U.S. Navy ship- and air-launched anti-submarine weapon introduced in 1972, building on the Mod 1 baseline. It features upgraded electronics and warhead for improved homing and lethality.

DETAILS: “Mark 46” denotes the U.S. Navy’s standard lightweight ASW torpedo; “Mod 2” refers to the 1972 upgrade of the Mod 1 variant. It retains the 12.75‑in (324 mm) diameter and ~8 ft (2.59 m) length, with a weight around 508 lb (231 kg). Mod 2 adds a more powerful Mk 103 Mod 1 warhead and improved onboard computer enabling a snake search pattern. Guidance remains active/passive acoustic homing, with improved seeker electronics yielding a detection range around 460 m. Propulsion uses Otto fuel II monopropellant and a two-speed engine; performance is ~40 kn speed and range about 11 km.

TYPE: Lightweight ship/air-launched active/passive acoustic homing torpedo

FUNCTION: Launched from Mk 32 tubes or deployed from aircraft/ASROC, it uses gyroscopic stabilization and a pre-programmed search pattern (e.g., snake) to locate submarine targets via acoustic sensors. Once a target is detected, it switches to terminal active/passive homing and detonates on contact.

NOTE:
IOC: 1972
Manufacturer: Aerojet-General, Naval Ordnance Station Forest Park, Honeywell, USA
Operators: United States; exported to select NATO allies
Platforms: Surface vessels (Mk 32 tubes), ASROC, ASW aircraft (P‑3 Orion, SH‑60, etc.)

SOURCE:
NavWeaps “Post‑World War II Torpedoes of the United States”; Wikipedia “Mark 46 torpedo”; Weaponsystems.net “Mk 46 torpedo”