The Admiralty Regrets
The Thetis submarine was to become a tomb for the 99 men on board her in 1939 and for the Royal Navy it was to be its worst ever submarine disaster taking place just 40 miles from where the Thetis was built in Birkenhead.
During her maiden voyage, the Thetis, the pride of the Royal Navy, 99 men were to lose their lives, not in battle but as the result of a tragic accident.
HMS Thetis was a submarine built by Cammell Laird in Birkenhead, she was launched on 29 June 1938. After completion, trials were delayed because the forward hydroplanes jammed, but they eventually started in Liverpool Bay under Lieutenant Commander Guy Bolus.
HMS Thetis left Birkenhead for Liverpool Bay to conduct her final diving trials, accompanied by the tug Grebecock. As well as her normal complement of 59 men she was also carrying technical observers from Cammell Laird plus other naval personnel, a total of 103 men.
The first dive was attempted at about 14:00 on 1 June 1939. The submarine was too light to dive, so a survey of the water in the various tanks on board was made. One of the checks was whether the internal torpedo tubes were flooded. Lieutenant Frederick Woods, the torpedo officer, opened the test cocks on the tubes. Unfortunately, the test cock on tube number 5 was blocked by some enamel paint so no water flowed out even though the bow cap was open. tools to clear the test cocks had been provided but they were not used. The layout of the bow cap indicators was also confusing as they were arranged in a vertical line with the shut position for tube 5 on the dial in a different position from those of the other torpedo tubes, this led to the inner door of the tube being opened. The inrush of water caused the bow of the submarine to sink to the seabed 150 ft (46 m) below the surface.