Pegasus-class hydrofoil

ThePegasus-class hydrofoilswere a series offast attackpatrol boatsemployed by theUnited States Navy. They were in service from 1977 until 1993. Thesehydrofoilscarried the designation "PHM" for "Patrol Hydrofoil, Missile." ThePegasus-class vessels were originally intended for NATO operations in the North Sea and Baltic Sea. Subsequently, participation by other NATO navies, including Germany and Italy, ceased and the U.S. Navy proceeded to procure six PHMs, which were highly successful in conducting coastal operations, such asnarcoticsinterdiction and coastal patrol, in the Caribbean basin.
In the late 1960s,NATOdeveloped a requirement for a small, fast warship to counter large numbers ofWarsaw Pactmissile boats, such as theKomarandOsa classes, deciding that a hydrofoil would be the best way to meet this requirement. In 1970 AdmiralElmo Zumwalt, the newChief of Naval Operations(CNO), keen to increase the Navy's number of surface vessels in a cost-effective manner, committed the United States to the NATO program for a hydrofoil. The U.S. Navy proposed the PHM design as a NATO standard, with the program being led by the U.S. Navy, and an order placed for two prototypes in 1972.The Italian Navy and the West GermanBundesmarinesigned letters of intent to participate in the programme, with other NATO navies, including theRoyal NavyandCanadian Forcesstudying the project.The U.S. Navy planned to buy up to 30 PHMs, with 10 to be purchased by West Germany and four by Italy.
After Zumwalt's retirement, the Navy chose to funnel most of the money for the PHMs into larger vessels. This delayed the ongoing construction ofPegasus, and the other vessels were not started.Congresseventually forced the Navy to complete the vessels. The difficulties in project progression forced the other involved navies to abort their participation.
ThePegasus-class ships were powered by two 800horsepower(600kW) twin turbo-chargedMercedes-Benzdiesel engineswhen waterborne, using water jets (designed byAerojet),giving them a speed of 12knots(22 km/h; 14 mph). When foilborne, the ships were powered by aGeneral Electric LM2500gas turbine and a very large water jet, giving them a speed of over 48 knots (89 km/h; 55 mph).
Pegasusships were well armed for their size, carrying two four-rackRGM-84 Harpoonanti-ship missilesand anOto Melara 76 mmgun. The Harpoons, specifically, were capable of sinking far larger ships at distances in excess of 60nautical miles(110 km). The West German version would have carried theMM38 Exocet.
AsPegasuswas constructed several years before the rest of the series, there are some slight differences, such as thefire-control system.
All six vessels were constructed byBoeing, inSeattleat the Renton plant at the south end ofLake Washington. They were stationed atNAS Key West.Principal contractors, along with Boeing, wereSperry Corporationfor MK 92 Mod 1 fire control system,Hollandse Signaalapparatenand Sperry Corp. (under license) for WM 28 fire control system,OTO-Melarafor 76 mm gun, andNAVSECfor design support.
The technology was first pioneered byUSSTucumcari(PGH-2), where it successfully operated in Vietnam, but ultimately ran aground off Puerto Rico. It was judged to be more advanced than the GrummanFlagstaffwhich was built at the same time to the same requirements. The primary technology, also used in theBoeing Jetfoilferries, used submerged flying foils with waterjet propulsion.
The ships were retired because they were not judged cost effective for their mission in a Navy with primarily offensive missions rather than coastal patrol.When in hydrofoil form, the ships would use 1000 gallons of fuel per hour. When in surface ship form, the ships would use 100 gallons of fuel per hour.USSAriesPHM-5 Hydrofoil Memorial, Inc. obtainedAriesfor rehabilitation as a memorial located on the Gasconade River inGasconade, Missouriat38°40′15″N91°33′10″W﻿ / ﻿38.67083°N 91.55278°W﻿ /38.67083; -91.55278. All other PHMs in the class were sold for scrap. In the early 2000sGeminiwas converted into a yacht, but was abandoned by its owners in the 2010s and scrapped in 2017.