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USS Mount Whitney (LCC 20) ca. 1990.
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Class: BLUE RIDGE (AGC/LCC 19)
Design: SCB Project Nos. 400.65 and 400.66
Displacement (tons): 13,038 light, 18,874 full (LCC 19)
Dimensions (feet): 620' oa (original), 580' wl x 108' e, 82' wl x 27' max nav
Armament: 2-3"50T; (1974) 2-3"50T, 2-MK25 (Sea Sparrow) MLS; (19: 1985, 20: 1987) 2-3"50T, 2-MK25 MLS, 2-CIWS; (1992) 2-CIWS; (1998) 2-25mmS, 2-CIWS
Accommodations: 52 officers and 790 enlisted (LCC 19)
Speed (kts.): 22
Propulsion (HP): 22,000
Machinery: Steam turbines, 2 boilers (600psi), 1 screw
|19||BLUE RIDGE||31 Dec 1964||NSY Philadelphia||27 Feb 1967||4 Jan 1969||14 Nov 1970|
|20||MOUNT WHITNEY||22 Aug 1966||Newport News||8 Jan 1969||8 Jan 1970||16 Jan 1971|
|19||BLUE RIDGE||In Comm. 2022||--||--||--||--|
|20||MOUNT WHITNEY||In Comm. 2022||--||--||--||--|
Work on a new AGC began with a study of a Mariner-class conversion in 1960 followed by a single sheet of characteristics in November 1962 and preliminary characteristics circulated for comment in April 1963. In addition to her amphibious role the ship had a contingent function of serving as flagship for a fleet commander in place of the current cruisers. An early AGC design, SCB Design No. 248, utilized the AFS 1 hull and machinery with a much enlarged superstructure for the command spaces, and several tall masts for HF antennas. On 10 July 1963 a first Ship Characteristics Board working level meeting was held on the new AGC, now SCB Design No. 400.65. BUSHIPS Code 420 (the Preliminary Design Branch) presented its work on the design based on the AFS, but Code 450 (the Electronic-Electrical Design Branch) announced that it had just decided that it would require a flat-top configuration to provide a ground plane for antenna performance with minimum topside structure and absolutely no running rigging of any sort exposed to electronic radiation. (This also required putting the boats in sponsons and locating the helicopter hanger and shops below decks with an elevator.) After trying unsuccessfully to adapt the AFS 1 hull, Code 420 shifted to the LPH 2 hull as a more promising basis for the design, giving it a centerline bridge structure instead of an island. The substitution of a conversion, either of an AP 120 class (P2-SE2-R1) troop transport, a CVL-22 class AVT, or CC-3 (ex AVT 6, ex CVL 48) was then considered, but by 20 November 1963 all work focused on the new construction design based on the LPH 2 hull. Two ships were funded, one in Fiscal Year 1965, the other in 1966. Approved characteristics for an Amphibious Force Flagship (AGC), SCB Project No. 400.65, were promulgated on 24 January 1964 and updated as SCB Project No. 400.66 on 18 September 1964 with a final change on 28 August 1969. The complex final design was characterized as embodying the combined approximate characteristics of two shore based communication stations in a single hull.
Electronics were a driving factor in the design. The ships were intended primarily for an amphibious role, but they had a contingent function as flagships for numbered fleet commanders to replace the converted World War II cruisers then being used. They needed a clear upper deck on which several massive radio antennas could be placed with minimal interference. The flat deck would act as a ground plane for the antennas, greatly improving their efficiency. The ship had to be able to transmit simultaneously on 40 separate HF channels, which could only be done with broadband antennas. Massive broadband high frequency (HF) discage transmitting and receiving antennas were of primary importance because the ships would rely on HF radio to reach over the horizon to ships and to commands ashore. The ships also carried another kind of HF antenna, working at the upper end of the HF frequency range: a directional log-periodic troposcatter Yagi antenna mounted atop a lattice mast. A new technology, satellite relay, was just being introduced for longer-haul communications back to the United States, and a structural tower supported on bulkheads on the second deck was provided to ensure a strong and rigid foundation for the large Miser microwave satellite relay system, though Miser failed during development and much lighter SATCOM antennas were ultimately fitted. The tower also held a circular array of ECM, VHF (amphibious communications), and UHF (including NTDS) antennas. A height finding radar was also needed for the AGC air control function, and the AN/SPS-48 was ultimately provided along with an AN/SPS-40 air search radar and a masthead Tacan for aircraft navigation. The design also included a pair of Sea Mauler point defensive missile launchers, but this system also failed and instead two Mk 25 Sea Sparrow launchers were fitted several years after the ships entered service.
A new study of amphibious flagships conducted between February 1967 and April 1968 resulted in a plan that included construction of a third new AGC under the FY 1969 program. She was to have been designed from the outset for both amphibious force and fleet command functions while the first two were primarily fitted for amphibious forces. However on 9 Feb 1968 a Navy proposal to slip her to FY 70 was approved and as of early 1969 construction of the third new AGC (now LCC) had not yet been approved for FY 1970, funds being withheld pending a study of alternatives. Ultimately no new command ships were built, although two LPDs were converted to fleet flagships, LA SALLE (LPD 3) to AGF 3 in 1972 and CORONADO (LPD 11) to AGF 11 in 1980.
On 14 Sep 1968 SECNAV directed the redesignation of AGCs, AKAs, and APAs to LCCs, LKAs, and LPAs. OPNAV notice of 25 Sep 1968 stated that LCC 19-20, then building, were to be reclassified to LCC on dates determined by NAVSHIPS. A NAVSEA letter of 1 Oct 1968 requested officials at Newport News and Philadelphia to implement the new system on the AGCs they were building, and 1 Oct 1968 became the reclassification date for LCC 19-20. In October 1979 BLUE RIDGE relieved the cruiser OKLAHOMA CITY (CG 5) as flagship of the Seventh Fleet at Yokosuka, Japan, and in January 1981 MOUNT WHITNEY relieved ALBANY (CG 10) as flagship of the Second Fleet at Norfolk. Both ships are still in commission in 2022 as fleet flagships. MOUNT WHITNEY converted to a mixed USN (military) and MSC (civilian) crew in 2004, BLUE RIDGE remains USN-manned.
|19||BLUE RIDGE||FY 1965. Name assigned as AGC, to LCC 19 1 Oct 1968. Based at Yokosuka, Japan, in 2022 supporting the US Seventh Fleet.|
|20||MOUNT WHITNEY||FY 1966. To LCC 20 1 Oct 1968, name assigned 11 Dec 1968 as LCC. MSC assumed navigational operation of the ship 20 Sep 2004. Based at Gaeta, Italy, in 2022 supporting the US Sixth Fleet.|
Compiled: 29 Jul 2021
© Stephen S. Roberts, 2021
Sources: NARA: RG19 Item S-15 Entry 1024(UD) AQ1-A1/3, Norman Friedman, U.S. Amphibious Ships and Craft, (Annapolis, 2002).