HMT Tranquil

HMT Tranquil

Whilst training at Western Isles Signalman Brooks briefly joined HMT Tranquil (FY 920) from 23rd April 1942 to 29th April 1942 under command of Temporary Lieutenant William Postlethwaite, RNR.

Launched in 1912 as the Good Luck (1497), HMT Tranquil was a converted minesweeping trawler, one of many requisitioned by the admiralty in 1939.

On 2nd November 1940, T/ Ltnt. William Postlethwaite’s previous command HMT Rinovia had struck a mine off Falmouth. She sank in just 48 seconds. Fourteen men lost their lives. William was among the survivors taken to hospital in Falmouth. He enjoyed 14 days of survivors’ leave before being posted to HMT Tranquil. On 14th June 1942, she left Tilbury Dock after further repairs only to founder just 2 days later in an accident all too common with convoys running without lights.

Admiralty record ADM 358/765  suggests the merchant SS Deal, running without lights as part of Convoy CE 91, collided with HMT Tranquil as she too, running without lights, was on patrol in the Thames estuary. The collision took place at 02.35 on 16 June 1942. HMT Tranquil sank in Trinity Bay in 16′ of water, 5 miles SE of Goodwin Fork Buoy ( 51°13.08 N / 01°27.51 E.) One survivor of the Tranquil, Raymond Cobb, recalls that when he looked back from the water he could see “the old man” (William Postlewaite) standing in the wheelhouse when she sank.

The wreck became known as the ‘balloon wreck’. HMT Tranquil had been towing a barrage balloon when she sank. All that could be seen rising from the 16′ of water in which she lay was the cable with the balloon still attached. T/ Ltnt. William Postlethwaite was listed as missing and presumed dead. He is commemorated on Panel 8 – Column 1 of the Lowestoft Memorial.

Unaware of the fate that awaited Tranquil, my father’s brief training spell ended with a transfer, first to HMS Stronsay, then to HMS Fairy Knowe and finally to HMS Windermere.

'HMT Tranquil' have 2 comments

  1. 9th July 2023 @ 10:43 am Karen Grantham

    My name is Karen Grantham and I have just found out that my grand father George Grantham was on the Tranquil when it sank, he was the assist cook and was one of the 6 who died that day. My father who is also called George Grantham who sadly has Alzheimer’s told me his body was never recovered does anybody know why seeing it sank in 16metres of water? Would love anybody to comment if they have any further information


    • 10th July 2023 @ 9:04 pm Dave Brooks

      Hello, Karen, thanks for contacting the site. It looks like the wreck was given war grave status so the bodies would have been left in situ. Did you create this site – – it has a super photo of your Grandfather?

      Of the 174 ships lost in this area during the war (North Foreland), many were due to collision and mines, it may have been too dangerous to dive the wreck site.


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