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DD-963 SPRUANCE-class

The Major Fleet Escort Study in 1967 confronted a basic dilemma of analysts: determining a ship's characteristics requires detailed analysis, but determining force levels requires broad, campaign analysis. The ship design you choose affects the numbers required and that the Navy can afford. This study resulted in the decision to build a total of 31 Spruance class destroyers, a platform that remained an integral part of U.S. maritime strategy.

The results were quite clear despite the study's intricate methodology, or perhaps because of it: the marginal cost-effectiveness criterion clarified and unified the presentation of the very large number of variables and their interrelationships.

The conclusions were specific as to force level requirements, and the recommendations were sufficiently detailed, along with supporting rationale, for the AAW and ASW ship characteristics. The "AAW" MFE, predictably, was a dual capable AAW/ASW design. The "ASW" ship, less predictably in 1967, was to carry strong point defenses and multi-purpose helicopters.

An interesting recommendation was that the AAW ships be "single enders," because the number of escorts per escorted force was driven by ASW requirements, and in concept AAW systems were added to the already required ASW ships until the escorting force achieved AAW sufficiency, by the cost-effectiveness criterion. For various reasons, including the assumption that ASW escorts would use only active sonar, the rationale for single-enders turned out be a mistake.

The study team had the difficult task of simultaneously looking at individual ship characteristics and the AAW and ASW force levels with those characteristics to procure and operate; and at the same time, to determine the best mix of AAW and ASW MFEs. The study achieved this multi-faceted objective in a persuasive fashion by intelligent application of the marginal effectiveness criterion. A study strength was the sensitivity analysis to show the effects on force size of various important uncertainties. Despite the relative insensitivity of force levels to any particular uncertainty, there was enough variation to spawn constructive debate on the final force level, based on acceptable risk.

As to ship characteristics, the study was the basis for the DD-963 class' characteristics. The cost became 100% over original cost. There was a growth in number of personnel. Because expected full automation was not realized, the school house could not produce fully trained graduates. OJT still needed to complement the ships' specific peculiarities. Also, because IMAS at dockside did not assist as much as hoped.

The Litton design which changed from steam to gas turbines revolutionized the thinking toward Navy propulsion systems.

The study was less successful for AAW ships. The number of escorts it derived for each escorted force (e.g., 5-7 for CVBGs) endured for more than a decade, and the MFE Study levels were not satisfactorily replaced until the "Surface Combatant Force Level Study" of 1994, done by APL for N-86. The force level recommendations are also well supported, and while never met, were very influential.

                                           DX-1            DX-2a                 DXG-1            DXG-2
                                         1 screw                           1 SAM system
Displacement (fully                        3950             6000                  6250             7450
loaded) (tons)
Maximum                                      27              30                    30               30
sustained speed
Range (n.m./knots)                       4500/20          4500/20               4500/20           4500/20
Weapons                             BPDMS            BPDMS                 1 TARTAR D        2 TARTAR D
                                    1-5" L.W.        1-5" L.W.             1-5" L.W.         1-5" L.W.
                                    ASROC            ASROC                 ASROC             ASROC
                                    MK32             MK32                  MK32              MK32
Sensors                            Surface Radar     Surface Radar         Surface Radar     Surface Radar
                                    2D Air Radar     2D Air Radar          2D Air Radar      2D Air Radar
                                    -                -                     3D Air Radar      3D Air Radar
                                    SQS-26           SQS-26                SQS-26            SQS-26
Other                               Helo Facility    Helo Facility         -                 -
Average cost of                          $24.9/40         $31.5b/40             $42.6b/40         $55.4/20
steamships (600
psi) in modernized
yard ($
Annual operating                             2.8             3.2                   4.4              5.0
cost ($ millions)
Enlisted                                    194             216                   225               244
a Costs are for 20 DXG-1 and 40 DX-2 built with common hulls in one modernized yard.
b Configuration derived in study provides additional 7"gun 175-MM or 5-inch L.W. gun on
                            DX (1967) Recommended              DD963 Built (1975 - 80)
Displacement (Full Load) 5,800                                 7,800
Procurement Cost            $45M                               $80M ($250M)
Guns                        2  5"/54 LW                        2  5"/54 LW
ASW Sensor (no VDS)         SQS-26 or SQQ-23                   SQS-26 (VDS planned & canx)
Manning                     216                                296
Speed                       30 kts                             33 kts
Propulsion                  2 screws                           2 screws & Gas Turbine
BPDMS                       Needed Now!                        Added Much Later
LAMPS                       Needed                             1 SH-3 or 2 LAMPS
Endurance                    4500NM @ 20 kts PLUS... 6,000 @ 20 kts total

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