Knox-class frigate
Knox-class frigates were United States Navy warships, originally laid down as ocean escorts, but were all redesignated as frigates on 30 June 1975, in the 1975 ship reclassification plan and their hull designation changed from DE to FF.
Modifications were made to Joseph Hewes and subsequent ships of the class. The primary differences were slightly different arrangement of the "Officer's Country" staterooms with additional staterooms in the 01 level instead of the open deck between the boat decks. The stateroom on the port side under the bridge was designated as a "flag" stateroom, with additional staterooms for flag staff when serving as a flagship. These ships have been referred to as the Joseph Hewes-sub-class
Design
The 46 ships of the Knox class were the largest, last, and most numerous of the US Navy's second-generation anti-submarine warfare escorts. Designated SCB No. 199C, the Knox was planned as the follow-on to the twin /38 caliber gun armed s and the Tartar missile-equipped s. Their initial design incorporated the prior classes' pressure-fired boilers in a similar-sized hull designed around the massive bow-mounted AN/SQS-26 sonar, with increased endurance and reduced crew size. Anti-submarine armament was to consist of ASROC anti submarine missiles together with the QH-50 DASH drone helicopter, while defensive armament was to be the RIM-46 Sea Mauler short range anti-aircraft missile backed up by a single 5-inch/54 caliber Mark 42 gun.The design soon ran into problems, with the US Navy deciding to switch to conventional boilers, requiring a redesign, with the ships becoming longer and heavier in order to accommodate the less compact power plants. In 1965, Sea Mauler was cancelled, leaving the ships to complete without any surface-to-air missile system.
Ten ships were authorized in Fiscal Year 1964, sixteen in 1965, and ten each for FYs 1966, 67 and 68; six were canceled in 1968, and four more in 1969. While the FY64 and FY65 ships were ordered from four different shipyards, later ships were all ordered from Avondale Shipyards in order to cut costs. These ships were built on a production line, with prefabricated modules being assembled upside down, welded together and then rotated into an upright position. They were originally commissioned as destroyer escorts 1052–1097 in 1969–1974, but were redesignated as frigates on 30 June 1975.
The Knox class had been criticized for deck wetness and there were a number of instances of damage to the forward weapons mounts in heavy seas. In 1979, the class began to receive "hurricane bows" beginning with. The modification heightened the bow section, adding bulwarks and spray strakes to prevent burrowing into on-coming seas and better protect the forecastle armament.
The Knox class was the Navy's last destroyer-type design with a steam turbine powerplant.
Due to their unequal comparison to destroyers then in service, they became known to a generation of destroyermen as "McNamara's Folly."
These ships were retired from the US Navy at the end of the Cold War due to their relatively high running costs, a declining defense budget, and the need for ships with a more advanced antisubmarine capability. None of the ships served more than 23 years in the US Navy, and by 1994, all of the class had been retired, although some remain in service with foreign nations such as Egypt, Taiwan, Thailand, and Mexico.
Construction
The lead ship of the class,, was laid down 5 October 1965, and commissioned 12 April 1969, at the Todd Shipyards in Seattle, Washington.The Knox class have a displacement of, with a full load. They are long overall and at the waterline, with a beam of and a draft of. The steam plant for these ships consists of two Combustion Engineering or Babcock & Wilcox "D" type boilers, each equipped with a high-pressure forced draught air supply system, with a plant working pressure of and superheat and rated at driving a single screw. This gives them a speed of.
These ships were designed primarily as anti-submarine warfare platforms. As built, their main anti-submarine sensor was the large bow-mounted AN/SQS-26CX low-frequency scanning sonar, operating as an active sonar at a frequency of about 3.5 kHz and passively at 1.5–4 kHz. The active modes of operation included direct path, to a range of about, bottom bounce, and convergence zone, which could give ranges of up to about, well outside the capability of ASROC, and requiring the use of a helicopter to exploit. Twenty-five ships of the class were refitted with the AN/SQS-35 Independent Variable Depth Sonar, an active sonar operating at about 13 kHz. The IVDS' sonar transducers were packaged within a 2-ton fiberglass-enclosed "fish" containing the sonar array and a gyro-compass/sensor package launched by the massive 13V Hoist from a stern compartment, located just beneath the main deck, to depths of up to. The IVDS could take advantage of water layer temperature conditions in close-range submarine detection, tracking and fire-control. The AN/SQS-35 "fish" was later modified to tow an AN/SQR-18A TACTASS passive towed array sonar.
As built, they were equipped with one 5-in/54 caliber Mark 42 gun forward, an eight-round ASROC launcher abaft the gun and forward of the bridge, with four fixed Mark 32 anti-submarine torpedo tubes. A helicopter deck and hangar for operating the DASH drone helicopter was fitted aft. The helicopter facilities were expanded in the 1970s to accommodate the larger, manned, Kaman SH-2D/F Seasprite LAMPS 1 helicopter. While as built, anti-aircraft warfare capabilities were limited to the 5-inch gun, it was planned to refit the ships with a short range surface to air missile system to replace the cancelled Sea Mauler. Thirty-one ships were fitted with an eight-round Basic Point Defence Missile System launcher for RIM-7 Sea Sparrow missiles, while was fitted with an improved NATO Sea Sparrow launcher. It was planned to equip the other 14 ships with Sea Chaparral, based on the Sidewinder air-to-air missile, but this plan was abandoned. Most ships were refitted with a Phalanx CIWS aft during the 1980s, replacing the Sea Sparrow launcher. Surface warfare weaponry was at first similarly limited to the gun, with several ships receiving an interim upgrade allowing Standard ARM anti-radar missiles to be fired from the ships' ASROC launcher in the 1970s. Later, all ships were modified to launch Harpoon anti-ship missiles from the ASROC launcher, which could carry two Harpoons, with two more carried in the ships' ASROC magazine.
''Baleares'' class
Five modified ships were built in Spain for the Spanish Navy as the s.''Chi Yang'' class
In the 1990s, the US agreed to transfer eight Knox-class frigates to the Republic of China Navy. The ROCN, anticipating future difficulties in maintaining the steam plants on these ships, originally contemplated an ambitious plan to replace these plants with diesel engines. However, due to budget considerations and the acquisition of newer ships, this plan is now believed to have been shelved. These frigates were renamed the Chi Yang-class and assigned to the ROCN 168 Patrol Squadron.By 2005, the ROCN had removed several systems from the retired upgraded World War II-vintage destroyers and transferred them to seven of the Chi Yang class. These systems include SM-1MR Standard missile in box launchers, H-930 modular combat system, and DA-08 air/surface search radar. Each Chi Yang-class frigate has 10 SM-1 missiles installed in two forward twin box launchers on top of the helicopter hangar, and two triple box launchers installed between the stack and the hangar, pointing to port and starboard. Chi Yang did not receive the upgrade.
The ASW capability of the Chi Yang class is provided by its SQS-26 bow-mounted sonar, SQS-35 VDS, SQR-181 passive TAS, MD500 ASW helicopter, Mk-16 8-cell Harpoon/ASROC box launcher, and four Mk46 torpedoes. While on ASW patrol, the frigate will carry two Harpoon SSMs and six ASROCs in its Mk-16 box launcher.
There are some speculations that these ships will probably be upgraded with Hsiung Feng III missiles.
Units
| Ship Name | Hull No. | Builder | Commission– Decommission | Fate | Link |
| FF-1052 | Todd, Seattle | 1969–1992 | Sunk as target | ||
| Roark | FF-1053 | Todd, Seattle | 1969–1991 | Scrapped | |
| Gray | FF-1054 | Todd, Seattle | 1970–1991 | Scrapped | |
| Hepburn | FF-1055 | Todd, San Pedro | 1969–1991 | Sunk as target | |
| Connole | FF-1056 | Avondale | 1969–1992 | To Greece, renamed Ipirus Sunk as target | |
| Rathburne | FF-1057 | Lockheed | 1970–1992 | Sunk as target | |
| Meyerkord | FF-1058 | Todd, San Pedro | 1969–1991 | Scrapped | |
| W. S. Sims | FF-1059 | Avondale | 1970–1991 | Grant aid to Turkey as spare parts hulk | |
| Lang | FF-1060 | Todd, San Pedro | 1970–1991 | Scrapped | |
| Patterson | FF-1061 | Avondale | 1970–1991 | Scrapped | |
| Whipple | FF-1062 | Todd, Seattle | 1970–1992 | To Mexico, renamed Almirante Francisco Javier Mina | |
| Reasoner | FF-1063 | Lockheed | 1971–1993 | To Turkey, renamed Kocatepe | |
| Lockwood | FF-1064 | Todd, Seattle | 1970–1993 | Scrapped | |
| Stein | FF-1065 | Lockheed | 1972–1992 | To Mexico, renamed Ignacio Allende | |
| Marvin Shields | FF-1066 | Todd, Seattle | 1971–1992 | To Mexico, renamed Mariano Abasolo | |
| Francis Hammond | FF-1067 | Todd, San Pedro | 1971–1992 | Scrapped | |
| Vreeland | FF-1068 | Avondale | 1970–1992 | To Greece, renamed Makedonia Decommissioned | |
| Bagley | FF-1069 | Lockheed | 1972–1991 | Scrapped | |
| Downes | FF-1070 | Todd, Seattle | 1971–1992 | Sunk as target | |
| Badger | FF-1071 | Todd, San Pedro | 1970–1991 | Sunk as target | |
| Blakely | FF-1072 | Avondale | 1970–1991 | Scrapped | |
| Robert E. Peary | FF-1073 | Lockheed | 1972–1992 | To Taiwan, renamed Chih Yang Decommissioned | |
| Harold E. Holt | FF-1074 | Todd, San Pedro | 1971–1992 | Sunk as target | |
| Trippe | FF-1075 | Avondale | 1970–1992 | To Greece, renamed Thraki sunk as target | |
| Fanning | FF-1076 | Todd, San Pedro | 1971–1993 | To Turkey, renamed Adatepe | |
| Ouellet | FF-1077 | Avondale | 1970–1993 | To Thailand, renamed | |
| Joseph Hewes | FF-1078 | Avondale | 1971–1994 | To Taiwan, renamed Lan Yang | |
| Bowen | FF-1079 | Avondale | 1971–1994 | To Turkey, renamed Akdeniz | |
| Paul | FF-1080 | Avondale | 1971–1992 | To Turkey as spare parts hulk | |
| Aylwin | FF-1081 | Avondale | 1971–1992 | To Taiwan, renamed Ning Yang | |
| Elmer Montgomery | FF-1082 | Avondale | 1971–1993 | To Turkey as spare parts hulk | |
| Cook | FF-1083 | Avondale | 1971–1992 | To Taiwan, renamed Hae Yang sunk as target | |
| McCandless | FF-1084 | Avondale | 1972–1994 | To Turkey, renamed Trakya | |
| Donald B. Beary | FF-1085 | Avondale | 1972–1994 | To Turkey, renamed Karadeniz | |
| Brewton | FF-1086 | Avondale | 1972–1992 | To Taiwan, renamed Fong Yang | |
| Kirk | FF-1087 | Avondale | 1972–1993 | To Taiwan, renamed Fen Yang | |
| Barbey | FF-1088 | Avondale | 1972–1992 | To Taiwan, renamed Hwai Yang | |
| Jesse L. Brown | FF-1089 | Avondale | 1973–1994 | To Egypt, renamed Dumyat | |
| Ainsworth | FF-1090 | Avondale | 1973–1994 | To Turkey, renamed Ege | |
| Miller | FF-1091 | Avondale | 1973–1991 | To Turkey as spare parts hulk | |
| Thomas C. Hart | FF-1092 | Avondale | 1973–1993 | To Turkey, renamed Zafer | |
| Capodanno | FF-1093 | Avondale | 1973–1993 | To Turkey, renamed Muavenet | |
| Pharris | FF-1094 | Avondale | 1974–1992 | To Mexico, renamed ARM Guadalupe Victoria | |
| Truett | FF-1095 | Avondale | 1974–1994 | To Thailand, renamed | |
| Valdez | FF-1096 | Avondale | 1974–1991 | To Taiwan, renamed Yi Yang | |
| Moinester | FF-1097 | Avondale | 1974–1994 | To Egypt, renamed Rasheed | |
| Unnamed | DE-1098 through DE-1100 | rowspan="2" | rowspan="2" | Cancelled 24 February 1969 | |
| Unnamed | DE-1102 through DE-1107 | - | - | Cancelled 24 February 1969 |