OVERVIEW: The Mk 46 NEARTIP Mod 5A(S) is a lightweight U.S. Navy torpedo introduced in 1997 under the Near‑Term Improvement Program, optimized for shallow-water anti-submarine warfare. It features dual-speed Otto fuel propulsion, enhanced digital sonar systems, and can operate in depths as shallow as 40 m.

DETAILS: “Mod 5A(S)” signifies the shallow‑water variant of the Mk 46 Mod 5A upgrade. It maintains the standard 12.75‑in diameter, ~8 ft length, and ~508 lb weight, with a 96.8 lb PBXN‑103 warhead. Digital CMOS-based control systems and new passive/active sonar significantly improve target detection and counter-countermeasure performance in littoral environments. Dual-speed operation (~30 kn search, >40 kn attack) yields an extended range of up to ~11 km. The “(S)” variant adds components enabling safe operation in waters as shallow as 40 m without risking seabed collision.

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

FUNCTION: Launched from Mk 32 tubes, aircraft, helicopters, or ASROC, it uses a quieter low-speed search mode in shallow water before accelerating in attack mode toward an acquired submarine target. Its digital guidance processes reduce false contacts and adapt to complex shallow-water acoustic conditions.

NOTE:
IOC: Circa 1997
Manufacturer: Alliant Techsystems, Honeywell, USA
Operators: United States; licensed by Japan and other allies
Platforms: Surface ships (Mk 32 tubes), ASW aircraft (e.g., P‑3 Orion), ASW helicopters (e.g., SH‑60), RUM‑139 VL‑ASROC
Conflict used in: No confirmed combat deployment

SOURCE: Mark 46 torpedo (Wikipedia); NavWeaps “Post‑World War II Torpedoes of the United States”; Display‑FactFiles U.S. Navy Mk 46 fact file; cmano‑db “Mk46 NEARTIP Mod 5A(S) (1997)”