Ton History

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At the end of the Second World War it was generally accepted that the emphasis on mining had shifted from deeply laid moored mines to ground mines laid in the shallow approaches to ports and harbours. The large steel-built ocean minesweepers were, therefore, mostly unsuitable for sweeping sophisticated modern mines laid in coastal and inshore waters. As a result, a team was formed at Bath in the UK in 1947 to design the next generation of minesweepers. This team produced two sets of hull drawings in 1949 for the construction of future inshore and coastal mine countermeasures vessels, each hull design being further sub-categorized into two variants, namely a minesweeper and a minehunter. Although no orders were initially placed, mainly owing to a lack of funding, the impending offensive in Korean waters led to the acquisition programme being brought forward to September 1950. The coastal minehunter variant was, however, suspended in June 1952 and cancelled altogether in March 1953, principally because of the lack of a suitable minehunting sonar at the time. Although the original names allocated to the coastal minesweepers were those of insects, this was later changed to villages in the UK ending in ‘TON’. The inshore minesweepers, in contrast, which were to have been known as the Bird Class, received names ending in ‘HAM’. The Ton Class proved to be a very successful design with over one hundred units built in the British yards between 1951 and 1960. Over thirty units were subsequently transferred to Commonwealth and foreign navies during the ensuing years, and the same basic design was also adopted by many Western navies for their own local construction programmes. John I. Thornycroft & Co Ltd, of Southampton, acted as parent firm to the group of fifteen smaller shipbuilders responsible for constructing these vessels, which were designed to sweep both moored and ground mines. With the exception of the double mahogany hull planking, almost the entire vessel was constructed from light aluminium alloy and other materials with the lowest possible magnetic field to achieve optimum safety when sweeping for magnetic mines. They were protected from pressure mines by their low displacement, and the threat of moored mines was greatly reduced by their shallow draught. To prevent potential damage caused by marine parasites, they were also fitted with a protective ‘Cascover’ nylon sheathing on the outer shell below the waterline.

  •  M1101-1115 were ordered on 9 September 1950 and were to be Red Ant, Blue Ant, Green Ant, Golden Ant, Red Aphis, Blue Aphis, Green Aphis, Golden Aphis, Red Bee, Blue Bee, Green Bee, Golden Bee, Red Beetle, Blue Beetle and Green Beetle.
  • M1116-1117 were ordered on 20 October 1950 and were to be Golden Beetle and Red Butterfly.
  • M1118-1127, ordered on 4 April 1951, were to be Blue Butterfly, Green Butterfly, Golden Butterfly, Red Centipede, Blue Centipede, Green Centipede, Golden Centipede, Red Cicala, Blue Cicala and Green Cicala.
  • M1128-1144, ordered on 28 September 1951, were to be Golden Cicala, Red Cockchafer, Blue Cockchafer, Green Cockchafer, Golden Cockchafer, Red Cricket, Blue Cricket, Green Cricket, Golden Cricket, Red Dragonfly, Blue Dragonfly, Green Dragonfly, Red Firefly and Blue Firefly & Golden Firefly.

Village names were allocated from March 1952;

  • M1145-1149 were ordered on 14 February 1952;
  • M1150-1151, on 19 March 1952;
  • M1152-1154 on 21 April 1952;
  • M1155-1167 on 22 March 1952;
  • and M1168-1186 on 17 June 1952.

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The design called for an aluminium-framed, wooden planked hull with non-magnetic fittings, capable of undertaking ocean passages, and the result was a double mahogany, copper plated and very sturdy craft which is still in service all over the world.

Early vessels had Mirrlees diesels, but from Highburton onwards the more powerful Napier Deltic was fitted, and eventually the original ‘Tons’ were re-engined. Early members of the class had an open bridge and the lead-ship Coniston had no top to her funnel and a short lattice mast, but subsequent vessels had a double-finned funnel top and covered bridges were progressively introduced. The last major external change was to revert to a tripod mast, for a new radar.

In 1964 Kirkliston was converted to a ‘minehunter’, with LL sweep gear removed and a minehunting Type 193 sonar installed in the hull beneath the bridge. Active rudders were fitted to allow her to position herself over the mine, and four divers and two inflatable boats were carried to permit the mine to be blown up by hand.

In Shoulton (who was converted to minehunter in 1963) an auxiliary diesel-hydraulic pump-jet system was installed in 1967 to provide quieter propulsion.

Another fourteen were modified to minehunters, some with the Sperry Towed Acoustic Generator (TAG) others with the Multiple Towed Gradiometer (MTG).

Iveston was fitted with Sonar 193M in 1971. It was the Plessey Company’s modernised version of the old 193 & was to be the prototype for the Hunt Class 193M Mod 0 & then 193M Mod1 sonar. She was attached to the 3rd MCMS at Portland for acceptance trials from 1972 for a couple of years before rejoining the Fleet in the 2nd MCMS.

Six ‘Tons’ were transferred to the Royal Australian Navy in 1961. Also four to the Indian Navy, one to Ghana, eight to South Africa, six to Argentina in 1968 and three to the Republic of Ireland in 1971.

  • Swanston, Somerleyton, Singleton, Alcaston, Chediston and Jackton became the Australian Gull, Hawk, Ibis, Snipe, Curlew and Teal; Curlew still being afloat, and currently under restoration by former crew member Gary Hamer in Tasmania, whilst Teal is now called the MV. NEAR EAST TEAL and is a University Training Vessel in Cyprus.
  • Aldington became the Ghanaian Ejura;
  • Whitton, Wennington, Durweston and Overton became the Indian Cannanore, Cuddalore, Kakinada and Karwar;
  • Thankerton, Dilston, Essington, Hexton, Darlaston and Lullington became the Malaysian Brimchang, Jerai, Kinabulu, Ledang, Mahamiru and Tahan;
  • Rennington, Santon, Ilmington, Hickleton, Tarlton and Bevington became the Argentine Chaco, Chubut, Formosa, Neuquen, Rio Negro and Tierra del Fuego.
  • Alverton, Blaxton and Oulston became the Irish Banba, Fola and Grainne.
  • Dunkerton, Hazleton, Castleton, Stratton, Packington, Oakington, Dumbelton and Chilton became the South African Pretoria, Kaapstad, Johannesburg, Kimberley, Walvisbaai, Mosselbaai, Port Elizabeth and East London. The South African Government also commissioned two purpose-built Ton Class vessels, the Durban and the Windhoek. Durban is now a Museum Ship in Cape Town and Dunkerton was a Diving Sports Boat, re-named MV. MADIBA after Nelson Mandela and lastly sporting her original name Golden Firefly before she was sadly broken up recently due to old age.
  • Packington is currently undergoing conversion to luxury yacht in Dubai, after starring in the movie ‘A LIFE AQUATIC’ released in 2004.

Two, Edderton and Sullington, became the survey vessels Myrmidon (20 July 1964) and Mermaid, while Invermoriston became an air-sea rescue vessel and Laleston was converted to a diving tender.

Myrmidon (Edderton) was later sold on to Malaysia, in 1969, to become Perantau ( This means ‘A Rover’)

The French, Canadians and Dutch were given the drawings to copy.

Many have served as RNVR/RNR tenders, reverting to their original names when replaced by others: Thames (Alverton, Buttington, Woolaston), Venturer (Hodgeston, Buttington), Burnicia (Kedleston), Clyde (Amerton, Crichton), Humber (Bronington), Mersey (Amerton, Pollington), Solent (Warsash, ex-Crofton), Curzon (Bickington, Fittleton), Killiecrankie (Bickington, Derriton), St David (Crichton), Kilmorey (Alfriston, Kirkliston), Warsash (Alfriston, Boulston, Crofton), Montrose (Dalswinton, Nurton, Chediston) and Northumbria (Quainton, Hodgeston).

Late in 1971, five were converted to coastal patrol craft with ‘P’ numbers – Beachampton (P1007), Monkton (P1055), Wasperton (P1089), Wolverton (P1093) and Yarnton (P1096), and a second 40mm/60 Mk 7 fitted abaft the funnel; All five were sent to Hong Kong. These Ton class Minesweepers were superseded by the Peacock class, more specialised for the job, but they provided excellent service whilst they were there.

Minehunter conversions consisted of Kirkliston, Shoulton, Bossington, Brereton, Bronington, Derriton, Glasserton, Highburton, Hubberston, Iveston, Kellington, Sheraton, Bildeston, Brinton, Gavinton, Kedleston, Maxton and Nurton.

15 Responses to Ton History

  1. Hi Bob. I want a photo of a Christmas card with Sgavington on the front. I sent it to the association a long time ago and i have lost the original card. It is also on the screen saver.Who do i contact to get a copy.

  2. Hi Bob
    Trying to register on Forum no luck please help.
    Yours aye

    • John,
      You have informed me that you have now been able to register and have access to the Forum now.
      I hope all is working well and that we hear from you soon.
      Best wishes

  3. Thanks Bob

    Yep in at last, its been a while since I last viewed the site and some considerable changes, so will have a good look around and hopefully spot something from my sweeper “Letterston”. Still got very fond memories of my time on her.
    Also very sad to see the demise of Bronnington, which I used to visit when I was in the area and she was moored near the war museum in Manchester.

    Thanks again

    • Hi John,
      We got there at last.
      I hope you like the site but please be aware that certain areas are still under construction. All contributions and constructive criticism welcome.
      Best wishes

  4. Hi Bob.

    I’m currently writing a paper about the Tons as part of my degree. Thank you for all your efforts with this site, it’s been a great starting point to base a lot of my research on. However, there’s a few things that don’t seem to be covered here, and I’m having trouble locating these pieces of information. I wondered if you might be able to help me at all?

    The things I’m stuck on are:
    – safety: what safety measures were there in place, and what standards had to be adhered to?
    – classification: which society was responsible for Ton classification, and where might I be able to find more details? I’m currently exploring Lloyd’s Register’s records, am I on the right track?
    – communications: do you know what radio or communications equipment the Tons used? I’ve found data for contemporary frigates, but nothing for MCMVs.
    – ballast: did they carry any ballast, and if so what type/s and where?
    – internal layout: what was the internal layout of the Tons?

    Thanks very much for any time and help, and once again for the great site. It’s been a really interesting read.

    Look forward to hearing from you soon,

  5. I am currently doing a qualification, called EPQ or extended project qualification, at my school Belfair’s high school in Leigh on sea in Essex. For my project I wish to make a DVD on the HMS Wilton as it currently serves as the Headquarters to the Essex yacht club of which I am a member.
    I am writing to you to ask if you would happen to have any video archives of the ship or any information that I can use in my documentary.
    Any help would be much appreciated and I would be happy to send you a final copy of my film afterwards.
    Thank you and hope to hear back soon
    Jack Veitch

    • Jack sorry it has taken a time to reply but the last two weeks have not been easy what with a funeral and a bereavement. Next two weeks are also going to be trying.
      However we do not hold any video on the Wilton I regret to say. I can supply you with a copy of the ships history that we hold. Please be aware that it may not be complete but may be of some assistance.


  6. Dear Bob,
    I wonder if you could tell me of the fate of ‘Thames’ – ex. Alverton – I was in the London Division RNVR / RNR from 1956 to 1964 and had many memorable weeks and w/ends in her but have only 1 photo of her.


  7. Bob,
    I appeared to read the ‘capcha’ incorrectly but I hope this is right!

  8. Hi
    Just been given link to this site, I served on couple of Ton Sweepers, surprised that the History of the Ton Class seems to have forgotten M1158 HMS Laleston converted in the 60’s to a clearance diving training vessel complete with decompression chamber and ran with original Mirrless Engine’s and open bridge until the very end. I served onboard as POME 1970 -1972 she was still running when I left service.
    For sure the last working Ton Class with Mirrless Engines

    • Ted what makes you think we have forgotten the Laleston? If you are referring to the page for her on this website I agree there is little there. However I am still trying to populate all the records which is quite a job given there are over a hundred to do on the Ton ships alone.
      If you can obtain a copy of “The Last Of The Wooden Walls” or its companion publication “Jacks Of All Trades” you will see she is given as much coverage as the other Tons.
      I will try and rectify this omission asap.
      Best wishes

  9. Hi
    I hope someone can help me. Does anyone know if there are any plans to mark the 40th anniversary of the loss of HMS Fittleton this year?
    My dad was Fred Pilgrim one of the 12 lost. I did have an email address for someone but I cant find it!
    Many thanks
    Nigel Pilgrim

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