` ALACRITY (AG 520) Class
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USS Assurance (AG 521) in a photo received in 1977.
Click on this photograph for links to larger images of this class.

Class: ALACRITY (AG 520)
Design: SCB 45B (Navy MSO 519)
Displacement (tons): 801 light, 934 full
Dimensions (feet): 190' oa, 182' wl x 36' e/wl x 12'
Armament: none
Accommodations: 8 officers, 75 enlisted
Speed (kts.): 15
Propulsion (HP): 2,700
Machinery: Geared diesel, 2 screws

Construction:
AGNameReclasBuilderKeelLaunchComm
520ALACRITY1 Jun 1973Peterson3 May 19568 Jun 1957COMM
521ASSURANCE1 Mar 1973Peterson28 Jan 195731 Aug 1957COMM

Disposition:
AGNameTDecommStrikeDisposalFateMA Sale
520ALACRITY30 Sep 197730 Sep 19771 Jul 1978Navy sale--
521ASSURANCE30 Sep 197730 Sep 19771 Jul 1978Navy sale--

Class Notes:
Approved characteristics for an Ocean Minesweeper (MSO) of a new 182' type (wooden hull), SCB Project 45B, were promulgated on 16 March 1955 and three MSOs were ordered to this design on 26 Oct 1955 from Peterson. (Project 45A for a Minesweeper (AM) had been promulgated on 10 Sep 1953.) On 11 Jun 1970 the first of the three ships, ABILITY (MSO 519), began a SCB 502.69 minehunter modernization (approved characteristics promulgated 31 July 1965 and 27 May 1970) under a contract of 2 Feb 1970 with Todd, Brooklyn, but the project was cancelled on 16 Oct 1970 and MSO 519 was struck on 1 Feb 1971 and sold on 3 Dec 1971. It was planned to inactivate her two sisters as well but this was cancelled in mid-December 1970 and they resumed mine warfare operations.

On 18 January 1973 CNO reclassified MSO 521 (ASSURANCE) to AG 521 effective 1 March 1973 and MSO 520 (ALACRITY) to AG 520 effective 1 June 1973. On 23 March 1973 ASSURANCE sailed to Fort George Island, Florida, for overhaul by the Atlantic Drydock Corp. During this work her minesweeping gear was removed and she was converted for use as a sonar research ship, the most visible conversion feature being the replacement of the minesweeping cable reels aft of the stack with a deckhouse. From 10 May to 23 July 1973 ALACRITY underwent similar modifications at Detyen's Shipyard in Mount Pleasant, S.C., followed by further alterations at the Atlantic Drydock Co. from 7 August to 19 October 1973. ASSURANCE operated off Port Everglades, Florida, for tests in November 1973 and in the Bahamas in January 1974, both probably related to the underwater sound ranges there. During the second half of 1974 she and ALACRITY operated with the 6th Fleet in the Mediterranean. ASSURANCE returned to the Caribbean during the first third of 1975 and conducted special operations in the western Atlantic Ocean in April-June 1976 and again in April 1977.

Ship Notes:
AGNameMANotes
520ALACRITY(ex-MSO 520,ex-AM 520, comm. 1 Oct 1958). Reportedly resold 28 Dec 1979.
521ASSURANCE(ex-MSO 521,ex-AM 520, comm. 21 Nov 1958).

Page Notes:
Compiled: 18 Oct 2021
© Stephen S. Roberts, 2021