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by Lt Cdr Geoffrey B Mason RN (Rtd) (c) 2001

HMS ONYX (J 221) - Algerine-class Fleet Minesweeper

HMS Onyx (Navy Photos/Mark Teadham, click to enlarge) return to Contents List 

ALGERINE-Class Fleet Minesweeper fitted with Turbine propulsion machinery ordered on 15th November 1940 from Harland and Wolff, Belfast. Laid down on 24th November 1941 at the same time as sister ship MUTINE. The ship was launched on 27th October 1942 as the seventh RN ship to carry this name, introduced in 1808 for a ten gun Brig Sloop sold in 1819 and last borne by a Torpedo Gunboat built in 1892 and renamed VULCAN II during June 1919. Her build was completed on 26th March 1943.and she had been adopted by the civil community of Okehampton, Devon after a successful WARSHIP WEEK National Savings campaign held in February 1942.


B a t t l e   H o n o u r s


MANLY 1809* - NORTH SEA 1943 - ARCTIC 1944 - NORMANDY 1944 - FALKLANDS 1982+

(Note: * = Single Ship action; + = Awarded Post WW2. See Post War Notes.)


H e r a l d i c   D a t a

Badge: On a field Red, upon a lozenge White, a lozenge engrained Red,

charged with a like lozenge White.



D e t a i l s   o f   W a r   S e r v i c e


(for more ship information, go to Naval History Homepage and type name in Site Search



1 9 4 3


March               Contractors trials and commissioned for service in 18th Minesweeping Flotilla.

                          (Note: This was the second Minesweeping Flotilla comprised of ALGERINE

                                     Class ships to be formed.)

      26th            Build completion and commenced Acceptance Trials.

                          On completion took passage to Tobermory for work-up and preparation for

                          operational minesweeping duties.


April                 After Work-up took passage to Port Edgar to carry out minesweeping training.

                         Commenced minesweeping training in Forth area.


May                  Deployed with HM Minesweepers COCKATRICE and ORESTES based at Londonderry

to July               for minesweeping in NW Approaches to ensure clear passage for coastal convoys.

                          (Note: These two minesweepers had also recently completed minesweeping training

                                       and were part of 18th Minesweeping Flotilla the remainder of which were

                                       deployed in the English Channel).


August              Deployed with HM Minesweepers READY, HOUND, HYDRA, LOYALTY,

                           COCKATRICE and newly joined HMS RATTLESNAKE for special

                           minesweeping operation in English Channel (Operation STARKEY)

                           (Note: This operation also included 9th Minesweeping Flotilla and was intended to

                                      draw attention of enemy aircraft which would then be vulnerable to attacks

                                       by RAF aircraft who were providing air cover.)


September         On release from STARKEY which proved unsuccessful returned to Harwich to resume

                           mine clearance in North Sea with Flotilla to ensure clear passage for East Coast convoys.

                           (Note: During Channel deployment the Flotilla came under shore fire from coastal

                                       batteries at Cape Gris Nez which damaged HMS HYDRA causing casualties and

                                       damage necessitating dockyard repair.)


October                North Sea deployment with Flotilla in continuation.

                              Nominated for duty in Home Fleet with Flotilla.


November             Passage from Harwich to Scapa Flow.

      15th                 Carried out anti-submarine patrol in northern waters for interception of U-Boats

                              on passage to and from attacks on Atlantic shipping. Although submarine contacts

                              were investigated these proved unsuccessful.

                              Allocated for duty in Iceland attached to Orkney and Shetland Sub-Command.

                              (Note: Did not join HM Minesweepers

December              Deployed for patrol and as Local Escort for convoys in NW Approaches.


1 9 4 4


January                  NW Approaches deployment in continuation.

      20th                 Deployed for Local Escort of Russian Convoy JW56B during initial stage of passage

                              from Loch Ewe with HM Destroyer WRESTLER, HM Corvette HONEYSUCKLE and

                              HMS HYDRA of Flotilla.

                              (Note: HM Destroyers  WHITEHALL, WESTCOTT, HM Sloop CYGNET, HM

                                          Corvette OXLIP and HM Minesweeper SEAGULL were also part of  Local

                                          Escort in NW Approaches.)

      26th                 Detached from JW56B after arrival of  destroyers of Home Fleet which were to escort

                              JW56B during remained of passage to North Russia,

                              For details of all Russian Convoy operations with names of merchant ships and

                              escorts, see CONVOYS TO RUSSIA by RA Ruegg, THE RUSSIAN CONVOYS by

                              B Schoefield, ARCTIC CONVOYS by R Woodman, CONVOY ! by P Kemp

                              and the Naval Staff History.)


February                NW Approaches deployment in continuation.

        8th                 Joined incoming Convoy RA57 from Kola Inlet as Local Escort with HM

                              Minesweepers HYDRA, LOYALTY, ORESTES  and READY for final stage of

                              passage to Loch Ewe. See above references for details.

      10th                 Detached from RA57 on arrival at Loch Ewe with Local Escort.


March                   NW Approaches deployment in continuation.

      27th                 Joined Russian Convoy JW58 with HM Minesweepers RATTLESNAKE,

                              ORESTES, HM Corvettes RHODODENDRON and STARWORT as Local Escort

                              during initial stage of passage from Loch Ewe to Kola Inlet.

      29th                 Detached from JW58 when ships of Home Fleet joined for escort during ocean

                              passage. See above references for details.

      30th                 Released from duties in NW Approaches and took passage to resume minesweeping

                              duties based at Portsmouth.


April                     Nominated for minesweeping support of planned allied landings in Normandy

                              (Operation NEPTUNE)

                              On return to UK ships of Flotilla were taken in hand for repair and maintenance

                              and to give shore leave to personnel after recent deployments.


May                             On resuming Flotilla duties joined Force G of Eastern Task Force and took part in

                                     preparatory exercises with Flotilla and ships of Force G prior to Operation/

                                     (Note: These included Exercise FABIUS II and a Defence exercise including all

                                                  Forces C, G and J which were to be deployed in the British Assault on

                                                  Normandy beaches.

                                     Carried out minesweep off Newhaven with ships of Flotilla and HM Minesweeper

                                     STORMCLOUD detonated an acoustic mine and sustained major damage.

                                     Returned to Solent to prepare for assault phase minesweeping operations.

                                     Allocated for clearance of Channel No 6 with HM Minesweepers READY (SO),

                                     COCKATRICE, HOUND, HYDRA, LOYALTY, RATTLESNAKE and

                                     ORESTES of Flotilla,


June                             Deployed in Solent.

       4th                        Operation delayed by 24 hours.

       5th                        Took passage for clearance of Channel 6.

                                     (Note: Four Danlayers and two Motor Launches were also attached to the Flotilla

                                                to assist in marking of the swept Channel.

       6th                         On completion of the sweep of Channel 6 deployed off beachhead for

                                     minesweeping to ensure safety of anchorage for unloading.

       7th                         Remained in Assault area for minesweeping.

                                     (For details of naval activities before and during Operation NEPTUNE see

                                     OPERATION NEPTUNE by K Edwards and LANDINGS IN NORMANDY June

                                     1944 (HMSO).

                                     In addition the Flotilla was deployed to provide a protective ring around the assault

                                     area which included night patrols to intercept enemy interference.

     30th                         On completion of NEPTUNE deployed for Channel minesweeping in Normandy

                                     area. Extensive minelaying was being carried out by midget submarine as well by

                                     other surface ships and aircraft. Mines laid included magnetic and acoustic types.


July                              Flotilla Channel minesweeping and interception patrol duties in continuation.

                                     (Note: During this period HM Minesweeper PYLADES on loan to Flotilla was

                                                  sunk by torpedo from a midget submarine.)


August                         Channel deployment in continuation.

to September                Carried out minesweeping operations of Le Havre.

                                     (Note: Ship may have been on detached service)


October                        On release from Channel duties took passage to Harwich

                                     Rejoined 18th Flotilla and prepared for minesweeping support of planned

                                     attack at Walcheren. Holland (Operation CINDERELLA)

                                     (Note: HM Minesweeper TANGANYIKA had joined Flotilla after completion

                                                  of minesweeping trials.)



       1st                         Deployed with Flotilla to provide clear area required for bombarding ships to

                                     naval gunfire support during landings at Walcheren for CINDERELLA.

                                     (Note: Bombarding ships were HM Battleship WARSPITE, HM Monitors

                                                 EREBUS and ROBERTS.

     10th                          Deployed off Ostend with HM Minesweepers READY, ORESTES, HYDRA,

                                      TANGANYIKA, HYDRA and COCKATRICE of Flotilla.

                                      (Note: HMS HYDRA detonated a mine during this operation and sustained

                                                   major damage. Although towed back to Sheerness the ship was

                                                   declared a Total Constructive Loss and never repaired.)


December                     Deployed with Flotilla for minesweeping of coast of Belgium and Holland.

                                      (Note: Military convoys and other shipping were carrying out support of

                                                  the allied forces in Europe, using ports which were available..

                                                  Extensive minelaying was being carried out by submarines and surface

                                                  craft to interfere with this traffic. See Naval Staff History and

                                                  HOLD THE NARROW SEA by P Smith.)


1 9 4 5


January                          Minesweeping duties with Flotilla to ensure clear passage for convoys to

to April.                         European ports in continuation. During this period operations were frequently

                                       affected by adverse weather including fog.


May                                Deployed with HM Minesweepers RATTLESNAKE, COCKATRICE,

                                       TANGANYIKA and ships of 10th Minesweeping Flotilla as escort for first

                                       convoy to enter Rotterdam.


June                                Remained in Channel and southern North Sea for mine clearance.

to August


P o s t   W a r   N o t e s


After VJ Day the ship remained with the Flotilla and after mine clearance off the East Coast of UK refitted at Devonport in September 1945. On completion she was deployed in Plymouth Command for similar duties in SW Approaches and the Bristol Channel. In March 1947 she was transferred to the 3rd Flotilla based at Port Edgar on the Forth until  August that year when she Paid-off and was reduced to Reserve status. Initially laid-up at Portsmouth the ship was moved to the Reserve Fleet Plymouth where she remained until placed on the Disposal List in 1966. Sold to BISCO for breaking-up by TW Ward this minesweeper arrived in tow at Inverkeithing, near Rosyth on 5th April 1967.



For more about Algerine-class Minesweepers, see



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revised 23/4/11
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