A plaque commemorating the submarine 'Thunderbolt' which was adopted by the town of Frome - in the Submarine Museum at Gosport
First launched at Cammell Laird’s in Birkenhead as HMS Thetis, this submarine was to have a doubly tragic history. On 1st June 1939 she was to make her first diving trial and with a complement of 103 persons on board, including other Naval Officers, employees of Cammell Laird and Vickers Armstrong, caterers and the Mersey Pilot, she headed out into Liverpool Bay.
Tragic errors in relation to her torpedo tubes led to a disastrous uncontrolled dive as a result of which 99 lives were lost off Anglesey. An 100th life was lost in the salvage process which brought the battered hull back to Cammell Laird’s where she was refitted and then, renamed as HMS Thunderbolt, joined the 3rd Submarine Flotilla. One critical modification was the introduction of a simple safety clip on the torpedo tube rear doors - universally known in the submarine service as a ‘Thetis Clip’.
From 1940 onwards HMS Thunderbolt saw action in the Atlantic and Mediterranean. In February 1942 she was adopted by ‘the citizens of the Urban and Rural Districts of Frome’. On 12th March 1943 was on her sixth Mediterranean patrol and engaged an Italian convoy. The convoy escort, commanded by an ex-submariner, gave chase and on the morning of 14th March dropped depth charges which immediately sank HMS Thunderbolt with the loss of all her crew.
The plaque commemorating the adoption and loss of HMS Thunderbolt was for some years located at St John’s Church in Frome and is now on permanent loan to the Royal Naval Submarine Museum at Gosport.