The design of the MHC is based on the Italian LERICI class of mine hunters. Constructed of glass-reinforced plastic, the ship is 188 feet long, has a beam of 36 feet, and displaces about 895 tons. Non-magnetic diesel engines drive cycloidal propellers. In another departure from conventional design, major machinery platforms are suspended from the main deck to provide acoustic isolation and shock dampening.

The combat system includes the AN/SYQ-13 Navigation, Command, and Control System; the AN/SLQ-48 Mine Neutralization System (MNS); the AN/SQQ-32 Minehunting Sonar; and .50 caliber machine guns.

The Navy completed a shock trial of USS OSPREY (MHC 51) in September 1995 at the Underwater Test Facility, Aberdeen Proving Ground, MD. Although the MHC 51 Class ship is not under DOT&E LFT&E oversight, the MHC 51 Shock Trial was of special interest because it was the first U. S. Navy Shock Trial on a hull constructed mostly of composite material. It provided an opportunity to study the shock response of a composite hull and assess the effectiveness of shock-isolated-cradle structures in protecting shipboard equipment. It was also the first Shock Trial at a land-based facility. The Navy extrapolated trial results to full design level shock conditions and instituted the design changes deemed appropriate and feasible. Preliminary results of this Shock Trial were addressed in the classified version of our 1997 annual report. The Navy's final report was received by DOT&E in October 1998 and is addressed in the MHC B-LRIP report.

The TEMP approved by DOT&E in 1995 called for a series of three operational tests. Two of the tests were to be conducted in 2QFY96 to evaluate mine hunting effectiveness (OT-IIIA) and mine sweeping effectiveness against moored mines (OT-IIIB). The schedule for a third test to evaluate the MHC's influence mine sweeping effectiveness (OT-IIIC) was undetermined because of program uncertainties. The Navy subsequently canceled plans to field modular mine sweeping systems for the MHC, obviating the requirement for OT-IIIB/C as described in the TEMP. Shock trial preparations and post-shock repairs delayed the start of OT-IIIA to 2QFY97.

OT-IIIA commenced March 24, 1997 at the Coastal Systems Station, Panama City, FL, aboard USS OSPREY with the Deputy Director, Conventional Systems and members of his staff embarked. The test plan approved by DOT&E prescribed three phases of testing over a one-month period. Test scenarios focused on mine hunting, mine neutralization, and navigation precision in test minefields containing practice versions of U.S. and threat mines. Operational suitability data was collected over the entire test period.

On April 3, 1997 after completing underwater survey operations and shallow water mine hunting and neutralization as scheduled, testing was suspended to investigate anomalous behavior of the variable depth sonar. With the cause of the sonar problem still unidentified, OPTEVFOR discontinued testing on April 11, 1997. According to information provided by the Navy, the source of the problem was subsequently traced to an installation error and corrected.

The deep-water phase of testing was performed by USS BLACK HAWK (MHC 58), upon the ship's return from a NATO countermine exercise. After a brief grooming period, testing required by the TEMP was completed between September 19-October 1, 1997.

The Navy's report on OT-IIIA was received at the end of 1QFY98. DOT&E's subsequent activity focused on independent analysis of test data and preparation of the B-LRIP report.

OT-IIIA was conducted in accordance with the test plan approved by DOT&E and was adequate for the purpose of evaluating the operational effectiveness and suitability of the MHC; however, a lack of variety in environmental conditions, limited threat replication, and a relatively short test exposure make it necessary to qualify the test results.

COMOPTEVFOR assessed the MHC to be operationally effective but not operationally suitable. DOT&E determined that the MHC is capable of readily detecting, classifying, identifying, and neutralizing mines in favorable environmental conditions. See the classified version of this report for operational limitations and susceptibility issues.

Most aspects of MHC effectiveness were satisfactory. Navigation accuracy and precision meet all requirements; however AN/SYQ-13 Navigation/Command and Control System software faults can cause a loss of data during attempts to save or retrieve contact information. Also, extended slow speed operations such as mine hunting cause excessive carbon build-up in the propulsion engines. Much of the Navy's tactical guidance for surface mine countermeasures is out of date and unnecessarily difficult to comprehend and apply.

The MHC is not operationally suitable primarily because of the unsatisfactory reliability and maintainability performance of the AN/SQQ-32 sonar and AN/SLQ-48 Mine Neutralization System and less than adequate logistics support. These factors were also responsible for below-threshold operational availability. The technical documentation is inadequate for equipment maintenance. The training of maintenance personnel is also suspect as evidenced by the test ships' excessive reliance on civilian technicians for assistance with sonar and Mine Neutralization System repairs. DOT&E's B-LRIP will be included in next year's annual report.