The Doomed Crews of the HMS Thetis and HMS Thunderbolt

The Doomed Crews of the HMS Thetis and HMS Thunderbolt

Larry Holzwarth - September 19, 2017

During the years following the First World War Western navies, particularly England’s Royal Navy, struggled to catch up with the submarine technology and tactics with which the German Navy had nearly brought England to ruin. The German Navy had proven the submarine to be an offensive weapon to reckon with. This did not sit well with their British cousins, who considered Britannia to still rule the waves, although the British did concede that modern naval warfare meant using submarines against maritime enemies.

By the late 1930s, British shipyards such as Liverpool’s Cammell Laird were constructing T-class submarines, the largest yet built for the British Navy. The boats (seagoing submarines are called “boats” by their crews) were equipped with 10 hull penetrations for torpedo tubes, the most installed on any submarine of the day. While the ten torpedo tubes gave the boats considerable firepower they also presented a flooding hazard which could place the vessel in jeopardy of sinking. Eventually, 53 T-class submarines were built, four of which were to serve in the Royal Netherlands Navy. One of the submarines retained in the British Navy was christened HMS Thetis. Thetis was launched in June 1938 and began trials to prepare itself for Royal Navy service as Europe lurched towards World War II.

The Doomed Crews of the HMS Thetis and HMS Thunderbolt
HMS Thetis departing Cammell Laird Shipyards in the Mersey River, sometime in 1939. Royal Navy

Thetis experienced problems during her acceptance trials which delayed the boat’s commissioning into the Royal Navy. Initial problems were with the boat’s control planes, essential to the submarine’s ability to drive, operate safely submerged, and return to the surface. Other problems emerged with the torpedo tubes, which needed to be flooded with seawater to fire torpedoes. Submarine torpedo tubes contain a door which opens to the sea, allowing the torpedo to be ejected from the tube and a door which opens into the submarine, allowing a torpedo to be loaded into the tube. Interlocks prevent both doors from being opened at the same time, an obviously inadvisable circumstance.

Thetis was not equipped with such interlocks, but instead with indicators which allowed the crew to ensure the status of the doors. Additionally, drain tubes were in place which would allow water to escape the tube if it were flooded and a crewman checked by opening a petcock, calling the crew’s attention to the tube’s status. Thetis was freshly out of the shipyard and thus freshly painted inside and out. The painters’ in their enthusiasm had painted over the openings to the drain tubes. The petcocks were painted shut.

In June of 1939, Thetis was operating in Liverpool Bay for torpedo trials prior to commissioning. The crew of Thetis was aware of the fact that the United States Navy submarine USS Squalus had sunk during test dives near Portsmouth, New Hampshire the preceding month, with the loss of 26 men. As Thetis began its trials the US Navy was attempting to rescue survivors from the stricken Squalus. At least in part due to the Squalus incident, Thetis had more than the usual number of escort vessels accompanying her during her test operations.

The Doomed Crews of the HMS Thetis and HMS Thunderbolt
HMS Thetis during salvage operations, 1939. Photo BBC

Thetis carried her normal crew of 59 officers and men accompanied by another 44 shipyard workers, technical advisors, and naval observers when she attempted to dive on June 1, 1939. The crew, unable to determine that the torpedo tube outer doors were open because the drain tubes were clogged with paint, opened the internal doors of at least one tube. Efforts by the inexperienced crew to correct the problem were complicated by overcrowded conditions, leading to uncontrolled flooding in the forward torpedo room.

Emergency surfacing procedures were initiated and Thetis raised its stern to the surface before heeling to port and beginning a dive. Thetis sank bow down in 150 feet of water. Most of the crew survived the initial sinking and after signaling to accompanying observation ships they prepared to abandon the submarine using prearranged escape procedures.

The submarine was equipped with an escape hatch which required the user (only one man could escape at a time) to follow procedures exactly or the system would be disabled for those following. After the first four men cleared the escape hatch one by one, the fifth escapee panicked as he attempted the procedure, disabling the escape mechanism and dooming the rest of the crew to a slow death from carbon dioxide poisoning.

Thetis was over 275 feet long, and a goodly portion of its hull remained above the surface of the water, tantalizingly exposed to rescuers who could do little to help the men aboard. The option of cutting air holes in the exposed stern of Thetis was considered and rejected as being too dangerous to the integrity of the hull and the safety of the would-be rescuers. Over the course of the next 48 hours, the crew aboard Thetis continued to breathe.

Ninety-nine men died as the natural result of their own exhalations. The Thetis disaster remains Britain’s largest loss of life in a submarine.

While Thetis remained helplessly crippled and the families of its lost mourned, the US Navy succeeded in raising USS Squalus (after a dramatic rescue, broadcast live on radio, in which 33 survivors of the sinking were saved). Squalus was raised in September 1939, returned to the shipyard, and eventually recommissioned as USS Sailfish. Under that name, it served throughout World War II, and was credited with sinking 20 Japanese ships for a total of more than 80,000 tons. Throughout its career it was forbidden for anyone of its crew, on pain of being marooned at the next port of call, to utter the word Squalus.

Efforts to salvage Thetis began as Squalus was being raised. At least one diver died while preparing to raise Thetis. The effects and dangers of narcosis – called “the bends” by divers – were as yet poorly understood, leading to the loss of Petty Officer Henry Perdue as preparations were made to bring Thetis back to the surface. By early September Thetis was raised off the bottom and – still submerged – deliberately grounded in Anglesey, on the Welsh coast. With England now at war with Germany efforts to prepare the submarine for service intensified.

The Doomed Crews of the HMS Thetis and HMS Thunderbolt
HMS Thunderbolt escorted by an unknown vessel in the Mediterranean about 1942. Photo Royal Navy

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.


Sources For Further Reading:

Sea Coast Online – USS Squalus Disaster Remembered 75 Years Later

New England Historical Society – The Greatest Submarine Rescue Ever: Saving the Squalus

BBC – Thetis Submarine Disaster

We Are the Mighty – The HMS Thunderbolt Was Lost with Almost All Hands. Twice!

BBC Channel – HMS Thetis Submarine Tragedy: Memorials Mark 75 Years