[drEaPer]

Found some useful information on the web by coincidence.
Especially the big active seeker range of 4000 yards made me wonder.

Mk.48 and Mk.48 ADCAP

The non-nuclear approach to the high speed, deep diving submarine was a very fast, deep diving torpedo with a high performance guidance system, that is, a much improved Mk.37 that would take full advantage of post-WW II technology. Consideration of such weapons, both submarine launched and air launched, began in November 1956 as part of the RETORC (Research Torpedo Re-Configuration) program. By 1960 a specific heavy weight torpedo project had emerged and designated first EX 10 and later Mk.48. Development characteristics for the new torpedo included a range of 35,000 yards at a speed greater than 55 knots and a 2500 ft depth limit. After a bidder qualification exercise and competition between the qualified bidders, a project definition contract was awarded to Westinghouse. A parallel contract was awarded to Clevite for the development of an alternative acoustic system. The Westinghouse contract was subsequently extended to include the development of the turbine powered Mk.48 Mod.0 which had only an ASW capability. Some Mod.0's were produced for evaluation, but by 1967 it had been decided that an anti-surface vessel capability was also needed. Some feeling persists that this was more a ploy to keep Clevite in the running than a significant operational requirement.

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14 These dates are from the unclassified versions of SecDef reports for the appropriate fiscal years.

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A competition between the Mk.48 Mod.1, which had emerged in rudimentary form from the Clevite contract, and Mk.48. Mod.2, a redesign of the Westinghouse Mod.0 followed. The Westinghouse torpedo used a Sunstrand turbine, as used in the Mod.0, for propulsion while Clevite used Otto fuel in an external combustion, axial piston engine. One of several selection factors was apparently the better efficiency of the piston engine, especially when running deep, as opposed to the quieter, but less efficient turbine. The acoustic systems were also somewhat different. In 1971 after competitive evaluation a full scale production contract was awarded to Gould15 (formerly Clevite). The first Mk.48 Mod.1 torpedoes were delivered to the fleet in 1972, twelve years after the development characteristics had been approved.

The Mk.48 Mod.1 torpedo was 21" by 230", weighed 3440 lb and carried a warhead with 650 lb of PBXN-103. Frequently published, but unofficial, data indicate that it was capable of 55 knots for 35,000 yards and could operate as deep as 2500 feet, but not at maximum speed. Its acoustic homing system is reported to have an acquisition range of 4000 yards, about four times that of the Mk.37. This performance is impressive and generally adequate for dealing with 30 + knot, deep-diving targets.

The Mk.48 torpedo is divided into five functional sections (groups) href="#fn16">16. These groups and their contents are briefly: 1) the nose, containing the acoustic system and the homing control logic (HCL); 2) the warhead, containing the high explosive, exploder and the Mk.12 electronic assembly, which is presumably a proximity fuzing device; 3) the control group, comprising the command, gyro and power control units; 4) the fuel tank containing not only the fuel but also the guidance wire dispenser; and 5) the afterbody/tailcone group comprising the engine, control surfaces and actuators, combustion chamber and the alternator. Most of the electronics was designed as functional item replacement (FIR) units (the approximate equivalent of aircraft line replaceable units) to reduce maintenance time and simplify the process. This concept also facilitates upgrading by installing new FIRs. The command control unit Mk.154, for example, was replaced by Mk.168 to accommodate the change to two way communication in the wire guidance system for Mk.48 Mod.3.

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15- Both the bureaucratic process and the contractor base have convoluted histories. The former occurred during the early McNamara years and rivals the TFX (F-111) in complexity and political undercurrents. Among the contractors, in 1969 Clevite and Gould merged with Gould being the surviving name. To further confuse the situation Westinghouse bought the Gould torpedo business in 1988. In March 1996 the Westinghouse defense and electronics business was sold to Northrop-Grumman. Gould produced the bulk of the Mk.48 torpedoes and Hughes and Westinghouse produced the ADCAPs.
16- This description is based primarily on Jane's Weapon Systems" 1986-87 and 1987-88 editions.

Its from http://www.geocities.com/Pentagon/1592/ustorp5.htm