Although Thetis had been named while under construction at Cammell Laird, the submarine had never been placed into commission as a Royal Navy vessel. By early 1940 Thetis was back at Cammell Laird under repair and was renamed. Sailor’s have long been a superstitious lot, ascribing many seemingly innocent actions to dooming a ship to bad luck, and renaming a ship is one of the worst. “What a ship was christened, so let her stay,” opined Long John Silver in Treasure Island. The new name – Thunderbolt – seemed to carry more than its share of poor luck as well. An HMS Thunderbolt – a sloop – had been wrecked off the African coast in the late 1840s. Another ship bearing that name eventually sank after colliding with a tug. Nonetheless, the Royal Navy opted to tempt Poseidon’s wrath and the late HMS Thetis became HMS Thunderbolt.
In the fall of 1940 HMS Thunderbolt joined the fleet and by the end of the year sank an Italian submarine in the Bay of Biscay. Thunderbolt was assigned to operations in the Mediterranean, where the principal opponent was not the Germans, but rather their Italian allies. All traces of the boat’s former identity as Thetis had been removed, and as in her American contemporary Sailfish, reference to the vessel’s former name was forbidden. Still, the crew of Thunderbolt daily viewed a haunting reminder of their boat’s earlier misfortune. Each compartment bore a high water mark in the form of a rusty smudge, which no amount of scrubbing could remove or fresh paint conceal.
By 1943 Thunderbolt had developed the reputation of one of His Majesty’s crack submarines. Seven enemy vessels had been dispatched by torpedo, another half dozen by gunfire in surface actions and Thunderbolt and her colleagues had largely driven the Italians into the safety of their harbors. Thunderbolt was converted to carry manned torpedoes, allowing the boat to stay outside the range of coastal guns while attacking shipping inshore. In January 1943 Thunderbolt’s manned torpedoes sank an Italian cruiser at anchor in the harbor at Palermo.
By early 1943 it seemed as if Thunderbolt had disproved the lie regarding a name change causing ill luck. But her luck was about to run out. In March, Thunderbolt sank the Italian freighter Esterel and in doing so drew the attention of the Italian corvette Cicogna. Cicogna was commanded by a former submariner, wise to the tactics of a submarine attempting to evade an enemy.
A grim duel developed, Thunderbolt submerged and increasingly desperate to escape; Cicogna relentlessly pursuing its prey. Minutes stretched to hours, hours to days, as the air on Thunderbolt grew increasingly foul. There was no lack of oxygen. The crew instead was beginning to be overcome by the increasingly high carbon dioxide content in the air. As in the case with the crew of the doomed Thetis, the men were poisoning themselves with each exhalation of breath.
After more than 48 hours of pursuit and evasion, Thunderbolt raised its periscope, probably hoping to find Cicogna gone and the way clear to surface and ventilate. Cicogna was waiting and immediately launched a depth charge attack. Shortly afterward Thunderbolt surfaced, stern first, before heeling over to port and beginning her final dive. This time the bottom was over 3,000 feet below. The Italians reported no survivors.
News of the second sinking of the submarine which had been both HMS Thetis and HMS Thunderbolt was withheld by the British Government for a time due to wartime secrecy concerns. The news was finally released by the British Admiralty and announced to the press and the world on June 1, 1943, four years to the day of the vessel’s first sinking.