Ton-class minesweeper

The Ton class were coastal minesweepers built in the 1950s for the Royal Navy, but also used by other navies such as the South African Navy and the Royal Australian Navy. They were intended to meet the threat of seabed mines laid in shallow coastal waters, rivers, ports and harbours, a task for which the existing ocean-going minesweepers of the Algerine class were not suited.

Description
The design of the class was led by the shipyard John I. Thornycroft & Company, and drew on lessons learnt in the Korean War, and numbered 119 vessels. They were diesel powered vessels of 440 tons displacement fully laden, constructed of wood and other non-ferromagnetic materials. Their small displacement and shallow draft gave them some protection against pressure and contact mines, and allowed them to navigate in shallow inshore waters. Primary armament was one Bofors 40 mm gun, although the South African variants also had an Oerlikon 20 mm cannon behind the funnel. RN vessels also had the same but they were gradually removed and an M2 Browning machine gun mounted midships. Sweeping equipment was provided for moored mines and magnetic mines.

Many of the class were converted to minehunters by the incorporation of active rudders and the installation of the Type 193 minehunting sonar and associated equipment, including a very welcome enclosed bridge (the exception being HMS Highburton who retained her open bridge until de-commissioning in the 1970s, this actually becoming a source of manliness to her crew when meeting other Ton crews). These vessels only retained mechanical "Oropesa" sweep capability.

The class served as patrol vessels in Borneo, Malaysia, Northern Ireland and Hong Kong. The minehunters played a significant role in the Suez Canal clearance after the Yom Kippur war. They also provided the backbone of the UK's Fishery Protection Squadron (4th MCM).

Five of the class in Royal Navy Service were permanently converted to patrol craft for service policing Hong Kong's territorial waters in 1971. These vessels, comprising HM Ships Beachampton, Monkton, Wasperton, Wolverton and Yarnton had their minesweeping gear removed and were fitted with a second Bofors 40 mm gun aft of the funnel. They also received new pennant numbers: Beachampton P1007, Monkton P1055, Wasperton P1089, Wolverton P1093 and Yarnton P1096.

It was originally planned to name the ships after insects, with names like Red Ant, Green Cockchafer and so on, but this plan was abandoned and the Royal Navy ships of the class were given names of British towns and villages ending in "-ton", hence the name of the class.

With the rundown of the Royal Navy fleet in the 1960s, many were sent to become base ships for the Royal Naval Reserve allowing reserve crews to get to sea for short periods without a lot of effort to organise a crew of significant size. Some of these had their names changed to reflect the RNR Division they were attached to.

The RNR vessels lasted until the introduction of the River-class minesweepers in 1984. The remainder of the RN ships paid off in the 1990s.

Ships
Royal Navy:
 * HMS Alcaston (M1102), launched 5 January 1953; sold to Australia in 1961 and renamed HMAS Snipe; broken up in 1985.
 * HMS Aldington (M1171), launched 15 September 1955; sold to Ghana in 1964 and renamed Ejura; broken up in 1979.
 * HMS Alfriston (M1103), launched 29 April 1953; broken up in 1988.
 * HMS Alverton (M1104), launched 18 November 1953; sold to Ireland in 1971 and renamed 'Banba''
 * HMS Amerton (M1105), launched 16 March 1953; broken up in 1971.
 * HMS Appleton (M1106), launched 4 September 1953; broken up in 1972.
 * HMS Ashton (M1198) (ex-Cheriton), launched 5 September 1956; broken up in 1977.
 * HMS Badminton (M1149), launched 14 October 1954; broken up in 1970.
 * HMS Beachampton (M1107), launched 29 June 1953; converted to Hong Kong Patrol craft 1971 and pennant number changed to P1007; sold in 1985.
 * HMS Belton (M1199), launched 3 October 1955; broken up in 1974.
 * HMS Bevington (M1108), launched 17 March 1953; sold to Argentina in 1968 and renamed Tierra del Fuego.
 * HMS Bickington (M1109), launched 14 May 1952; broken up in 1988.
 * HMS Bildeston (M1110), launched 9 June 1952; broken up in 1988.
 * HMS Blaxton (M1131), launched 26 January 1955; sold to Ireland in 1970 and renamed Fola.
 * HMS Bossington (M1133) (ex-Embleton), launched 2 December 1955; broken up in 1988.
 * HMS Boulston (M1112), launched 6 October 1952; broken up in 1975.
 * HMS Brereton (M1113), launched 14 March 1955; broken up in 1992.
 * HMS Brinton (M1114), launched 8 August 1952; sold in 1997.
 * HMS Bronington (M1115), launched 19 March 1953; became a museum ship in 1989.
 * HMS Burnaston (M1116), launched 18 December 1952; broken up in 1971.
 * HMS Buttington (M1117), launched 11 June 1953; broken up in 1970.
 * HMS Calton (M1118), launched 24 October 1953; broken up in 1968.
 * HMS Carhampton (M1119), launched 21 July 1955; broken up in 1970.
 * HMS Castleton (M1207), launched 26 August 1958; sold to South Africa in 1959 and renamed Johannesburg
 * HMS Caunton (M1120), launched 18 December 1952; broken up in 1970.
 * HMS Chawton (M1209), launched 24 September 1957; broken up in 1977.
 * HMS Chediston (M1121), launched 20 February 1953; sold to Australia in 1961 and renamed HMAS Curlew.
 * HMS Chilcompton (M1122), launched 6 October 1953; sold in 1971.
 * HMS Chilton (M1215), launched 15 July 1957; sold to South Africa in 1958 and renamed East London.
 * HMS Clarbeston (M1123), launched 18 February 1954; broken up in 1987.
 * HMS Coniston (M1101), launched 9 July 1952; broken up in 1970.
 * HMS Crichton (M1124), launched 17 March 1953; broken up in 1987.
 * HMS Crofton (M1216), launched 7 March 1958; broken up in 1987.
 * HMS Cuxton (M1125), launched 9 November 1953; broken up in 1992.
 * HMS Dalswinton (M1126), launched 24 September 1953; broken up in 1973.
 * HMS Darlaston (M1127), launched 29 September 1953; sold to Malaysia 1960 and renamed Mahamiru.
 * HMS Derriton (M1128), launched 22 December 1953; broken up in 1970. The machinery and fittings were reconditioned and installed in the prototype Glass Reinforced Plastic (GRP) minehunter HMS Wilton (M1116), launched on 18 January 1972 and commissioned on 14 July 1974.
 * HMS Dilston (M1168), launched 15 November 1954; sold to Malaysia in 1964 and renamed Jerai.
 * HMS Dufton (M1145), launched 13 November 1954; broken up in 1977.
 * HMS Dumbleton (M1212), launched 8 November 1957; sold to South Africa in 1958 and renamed Port Elizabeth.
 * HMS Dunkerton (M1144), launched 8 March 1954; sold to South Africa in 1955 and renamed Pretoria.
 * HMS Durweston (M1201), launched 18 August 1955; sold to India in 1956 and renamed Kakinada.
 * HMS Edderton (M1111), launched 1 November 1953; converted to a survey vessel in 1964 and renamed Myrmidon; sold to Malaysia in 1969 and renamed Perantau.
 * HMS Essington (M1134), launched 26 September 1956; Purchased Malaysia 1964 and renamed Kinabalu.
 * HMS Fenton (M1135), launched 2 December 1955; broken up in 1968.
 * HMS Fiskerton (M1206), launched 12 April 1957; broken up in 1977.
 * HMS Fittleton (M1136), launched 26 September 1956; broken up in 1977.
 * HMS Flockton (M1137), launched 3 June 1954; broken up in 1969.
 * HMS Floriston (M1138), launched 26 January 1955; sold in 1968.
 * HMS Gavinton (M1140), launched 27 July 1953; broken up in 1991.
 * HMS Glasserton (M1141), launched 3 December 1953; broken up in 1988.
 * HMS Hazleton (M1142), launched 6 February 1954; sold to South Africa in 1955 and renamed Kaapstaad.
 * HMS Hexton (M1143), launched June 1954; sold to Malaysia in 1963 and renamed Ledang.
 * HMNZS Hickleton (M1131), launched 26 January 1955; sold to Argentina in 1971 and renamed Neuquen.
 * HMS Highburton (M1130), launched 2 June 1954; Scrapped 1978.
 * HMS Hodgeston (M1146), launched 6 April 1954; broken up in 1988.
 * HMS Houghton (M1211), launched 22 November 1957; broken up in 1971.
 * HMS Hubberston (M1147), launched 14 September 1954; broken up in 1992.
 * HMS Ilmington (M1148), launched 8 March 1954; sold to Argentina 1967 and renamed Formosa.
 * HMS Invermoriston (M1150), launched 2 June 1954; converted to air-sea rescue vessel; broken up in 1971.
 * HMS Iveston (M1151), launched 14 October 1954; became a sea cadet training ship in 1993.
 * HMS Jackton (M1152), launched 28 February 1955; sold to Australia 1961 and renamed HMAS Teal.
 * HMS Kedleston (M1153), launched 21 December 1953; broken up in 1992.
 * HMS Kellington (M1154), launched 12 October 1954; Became a sea cadet training ship in 1993. Broken up in 2009.
 * HMS Kemerton (M1156), launched 27 November 1953; broken up in 1975.
 * HMS Kildarton (M1162) (ex-Liston), launched 23 May 1955; sold in 1969.
 * HMS Kirkliston (M1157), launched 18 February 1954; broken up in 1991.
 * HMS Laleston (M1158), launched 18 May 1954; broken up in 1985.
 * HMS Lanton (M1159), launched 30 July 1954; broken up in 1970.
 * HMS Letterston (M1160), launched 26 October 1954; broken up in 1971.
 * HMS Leverton (M1161), launched 2 March 1955; broken up in 1972.
 * HMS Lewiston (M1208), launched 3 November 1959; broken up in 1986.
 * HMS Lullington (M1163), launched 31 August 1955; sold to Malaysia in 1966 and renamed Tahan.
 * HMS Maddiston (M1164), launched 27 January 1956; broken up in 1975.
 * HMS Maryton (M1203), launched 3 April 1958; broken up in 1969.
 * HMS Maxton (M1165), launched 24 May 1956; broken up in 1989.
 * HMS Monkton (M1155) (ex-Kelton), launched 30 November 1955; converted to Hong Kong Patrol craft 1971 and pennant number changed to P1055; sold in 1985.
 * HMS Nurton (M1166), launched 22 October 1956; broken up in 1995.
 * HMS Oakington (M1213), launched 10 December 1958; sold to South Africa in 1959 and renamed Mosselbaai.
 * HMS Oulston (M1129), launched 29 September 1953; sold to Ireland in 1971 and renamed LÉ Grainne (CM10).
 * HMS Overton (M1197), launched 28 January 1956; sold to India in 1956 and renamed Karwar.
 * HMS Packington (M1214), launched 3 July 1958; sold to South Africa in 1959 and renamed Walvisbaai, then sold to the Walt Disney Company to portray the R/V Belafonte in The Life Aquatic with Steve Zissou.
 * HMS Penston (M1169), launched 9 May 1955; broken up in 1970.
 * HMS Picton (M1170), launched 20 October 1955; broken up in 1969.
 * HMS Pollington (M1173), launched 10 October 1957; broken up in 1987.
 * HMS Puncheston (M1174), launched 20 November 1956; broken up in 1977.
 * HMS Quainton (M1175), launched 10 October 1957; broken up in 1979.
 * HMS Rennington (M1176), launched 27 November 1958; sold to Argentina in 1967 and renamed Chaco
 * HMS Repton (M1167) (ex-Ossington), launched 1 May 1956; sold in 1982.
 * HMS Roddington (M1177), launched 24 February 1955; broken up in 1972.
 * HMNZS Santon (M1178), launched 18 August 1955; sold to Argentina in 1967 and renamed Chubut.
 * HMS Sefton (M1179), launched 27 November 1958; broken up in 1978.
 * HMS Shavington (M1180), launched 25 April 1955; broken up in 1987.
 * HMS Sheraton (M1181), launched 20 July 1955; sold in 1997.
 * HMS Shoulton (M1182), launched 10 September 1954; broken up in 1981.
 * HMS Singleton (M1183), launched 18 November 1955; sold to Australia in 1961 and renamed HMAS Ibis (M 1183).
 * HMS Soberton (M1200), launched 20 November 1956; sold in 1993.
 * HMS Somerleyton (M1139) (ex-Gamston), launched 1 July 1954; sold to Australia in 1961 and renamed HMAS Hawk (M 1139).
 * HMS Stratton (M1210), launched 29 July 1957; sold to South Africa in 1959 and renamed Kimberley.
 * HMS Stubbington (M1204), launched 8 August 1956; broken up in 1989.
 * HMS Sullington (M1184), launched 20 July 1955; converted to a survey vessel in 1965 and renamed Mermaid; broken up in 1970.
 * HMS Swanston (M1185), launched 10 September 1954; sold to Australia in 1961 and renamed HMAS Gull.
 * HMS Tarlton (M1186), launched 18 November 1955; sold to Argentina in 1967 and renamed Rio Negro.
 * HMS Thankerton (M1172), launched 4 September 1955; sold to Malaysia in 1966 and renamed Brinchang.
 * HMS Upton (M1187), launched 15 March 1956; broken up in 1991.
 * HMS Walkerton (M1188), launched 21 November 1956; used as Dartmouth Training Ship (Britannia Royal Naval College) in 1970s; broken up in 1990.
 * HMS Wasperton (M1189), launched 28 February 1956; converted to Hong Kong Patrol craft 1971 and pennant number changed to P1089; sold in 1986.
 * HMS Wennington (M1190), launched 6 April 1955; sold to India in 1956 and renamed Cuddalore.
 * HMS Whitton (M1191), launched 30 January 1956; sold to India in 1956 and renamed Cannanore.
 * HMS Wiston (M1205), launched 3 June 1958; broken up in 1982.
 * HMS Wlkieston (M1192), launched 26 June 1956; broken up in 1976.
 * HMS Wolverton (M1193), launched 22 October 1956; converted to Hong Kong Patrol craft 1971 and pennant number changed to P1093; sold in Hong Kong in 1986 and converted to a floating restaurant; destroyed in a fire in 1991.
 * HMS Woolaston (M1194), launched 6 March 1958; broken up in 1980.
 * HMS Wotton (M1195), launched 24 April 1956; broken up in 1992.
 * HMS Yarnton (M1196), launched 26 March 1956; converted to Hong Kong Patrol craft 1971 and pennant number changed to P1096; sold in 1986.

South African Navy:
 * SAS Durban (M1499).
 * SAS East London (M1215), ex-HMS Chilton – sold to Italian film company.
 * SAS Johannesburg (M1207), ex-HMS Castleton.
 * SAS Kaapstad, (P1557/M1210), ex-HMS Hazleton; ex-HMS Blue Firefly.
 * SAS Kimberley (M1210), ex-HMS Stratton.
 * SAS Mosselbaai (M1213), ex-HMS Oakington.
 * SAS Port Elizabeth (M1212), ex-HMS Dumbleton.
 * SAS Pretoria (P1556/M1144), ex-HMS Dunkerton; ex-HMS Golden Firefly – museum ship in Hout Bay.
 * SAS Walvisbaai (M1214), ex-HMS Packington (M1214) – sold to The Walt Disney Company.
 * SAS Windhoek (M1498).

Royal New Zealand Navy:
 * HMNZS Santon (M1178), 1965–1966, sold to Argentina and renamed ARA Chubat (M3) in 1967.
 * HMNZS Hickleton (M1131), 1965–1966, sold to Argentina and renamed ARA Neuquen (M1) in 1967.