9.40am, June 1st 1939, His Majesty's Submarine Thetis sailed from Birkenhead under the command of Lieutenant Commander G.H.Bolus (RN).
The purpose of the day was to make a diving trial. This was to be Thetis's first venture as a submarine proper. On board were 103 persons, fifty more than her normal crew. Of the extra fifty on board 8 were Naval Officers some commanding their own Submarines anxious to see the performance of this new class of Submarine. The others were employees of Cammell Laird and Vickers Armstrong. Also there were two employees of a catering firm on board for the reception that usually follows the trials, and finally the Mersey Pilot, Norman Willcox.
Thetis headed out to Liverpool Bay escorted by the Liverpool Screw Towing and Lighterage Company's tug Grebecock captained by Mr A E Godfrey. It was also the duty of the tug to take the passengers from Thetis before she commenced her first dive. At 1.30 p.m. the tug received a signal from Thetis that all passengers had decided to remain on board Thetis and that the dive would commence.
At precisely 2 p.m. there was a "whoosh" as air rushed out of Thetis tanks, clearly heard by the crew on board the tug, Thetis had opened her main vents. For the next 50 minutes the crew on board Grebecock watched the Thetis disappearing slowly below the surface in what was a dive in "slow time". She had her bow down a slight angle and appeared to have difficulty getting below the surface then, at 2.58 p.m. she suddenly disappeared beneath the waves.
From the its very construction onwards, through a combination of human error, delay and fate, it would appear that Thetis was doomed. Even when Lt. Cdr. Bolus ordered the dive, it was found that she was light and needed more weight forward. This entailed taking extra water on board. It was decided to check numbers 5 and 6 forward torpedo tubes which should have been filled with water to effect the ballast in the absence of torpedoes. The bow cap/outer door from which the torpedo leaves the submarine is opened to let in water if the tubes are to be flooded for ballast. Obviously the rear / inner door of the torpedo tube into which the torpedo is placed would have to be closed, otherwise the whole submarine would very quickly flood.
On these doors there are small holes that can be opened by a lever - a test cock. When this lever is turned / opened, the water will spill out in a controlled manner if the tube is full. No water drips indicate that no or at least very little water is present in the tubes and the inner rear door can then be opened. During the fitting, painting and subsequent enamelling of Thetis, these inspection holes did not seem to have been plugged to prevent blockage by paint etc and were painted over, creating a seal withinin the inspection plugs. This one simple factor was to have dire consequences for HMS Thetis.
Questions were being asked as to why Thetis was struggling to dive.Although the paper work showed no 5 and 6 tubes were filled with water as part of the trim procedure, it was decided to test no 5 tube. The rear inspection lever was opened for inspection but only a very small drip of water escaped indicating, little if any water present in No 5 tube. It was decided to opened the rear door of No 5 torpedo tube. It is unfortunate that at this stage no one was aware that the bow cap of no.5 tube was open, flooding no. 5 tube.
Extra manpower was needed to manoever the lever which was sticking, but it was finally with great difficulty pushed to the open position. A tremendous gush of sea-water knocked the men off their feet as the compartment quickly filled with tons of water, flooding the forward compartment. This sudden increase in weight forward forced the bow of Thetis further down in the water. At this precise moment, more power was applied to the engines and the angle of the hydroplanes put to "hard dive". This combination of events had the immediate effect of sending Thetis to the bottom in an uncontrolled dive. The men in the forward compartment struggled to close the hatch but one of the locking bolts caught between the hatch and the hatch seating. The impact of Thetis hitting the bottom, the lights failing, and the water tight hatch stuck, forced the men to abandon any further attempt to free the hatch. They scurried for safety into the second compartment. Unbelievably the same twist of fate was to happen again when the second compartment hatch jammed. Both compartments quickly flooded. Miraculously, they did manage to secure the hatch leading to the third compartment.
Thetis was equipped with two escape chamber, one right forward the other right aft, she also carried sufficient Deep Sea Escape Apparatus (D.S.E.A) for all 103 on board. In addition, she had sufficient air on board for approximately 36 hours. However, as Thetis had twice the number on board this was now reduced to 18 hours. Thetis settled on the bottom 160 feet below the surface and unknown to anyone 1 mile away from her escort on the surface, who by now was convinced something had gone horribly wrong with the dive.
The escort tug Grebecock, sent a signal to the shore support. Unfortunately the tug was not equipped for such an emergency nor was she capable of holding her position and had drifted in the strong current some 4 miles from the position Thetis lay. The Thetis and her position was lost and darkness closing in.
On board Thetis it was decided to empty the after tubes which would have the effect of raising the stern. Thetis was 270 feet in length so it would rise well out of the water that was 160 feet at that time. This was done leaving the stern of Thetis sticking 18ft out of the water! Unfortunately, it was now dark and Thetis was 4 miles from the search area. The after escape hatch through which any escape attempt was to be made was 20 ft below the water line. No escape attempt could be made until it was established that there was a surface craft above to retrieve the escaping crew. All that Thetis could do was wait. It would be a long night.
One hour after daylight a searching plane noticed a black object sticking out of the waterand finally confirmed that HMS Thetis had been found, the time was 0745, 18 hours since her dive and at the estimated limit that men could survive. Conditions on board were extreme, the men were very weak due to lack of oxygen. All on board would be suffering from headaches. Surface craft rushed to the area where Thetis was sighted and immediately hammered on the hull of Thetis to let her know help was at hand.
An escape attempt was being planned within the Thetis which would require the use breathing apparatus and entering the chamber, which would be filled with seawater. The hatch could then be opened for the escape 20 feet up to the surface. Onboard, two men - Oram and Woods, made their way to the escape hatch and put on their D.S.E.A equipment….within minutes the two were hurtling toward the surface and freedom. This success increased the hopes of all on board dispite the ever decreasing oxygen supply. Lieutenant Chapman organised that a second attempt be made this time with four men in the hatch Leading Stoker Kenny, Stoker Hole and two Cammel Laird Workers….unfortunately all four were to drown within the escape hatch. It was decided to try a further attempt, again in pairs. Leading Stoker Walter Arnold and Frank Shaw. They were successful!
The remaining men on Thetis were by now to weak to perform the necessary operation of securing the hatch in the escape chamber. It was certainly the last attempt to escape that caused for the second and final time two hatches to be opened at the same time. It will never be known how or why but at this last attempt the sea flooded the Thetis. Within seconds all occupants of His Majesty's Submarine Thetis succumbed to the abrupt rise in the concentration of carbon dioxide that the rapid increase of pressure instantaneously caused. Long before sufficient water had entered Thetis to bring about the struggle and fight against drowning, the merciful gas had quietly and quickly killed them all, many of them while they slept.
The sudden influx of tons of water flooding HMS Thetis put tremendous strain on the hawsers securing the stern of Thetis on the surface. It proved too much and the hawsers parted. Thetis disappeared below the surface and finally rested on the seabed of Liverpool Bay.
The German Chancellor, Herr Adolf Hitler sent a telegram conveying his own and the German nations sympathy over the disaster. A memorial service was held at sea aboard HMS Hebe for the families and collegues of those lost. Hebe was joined at the site of the disaster by a congregation of salvage vessels, lifeboats and various other craft all paying their respects. The service was held by Rev G H Crouch,RN.
In London on June 8th, a memorial took place at St Martin in the fields, led by the Archbishop of Canterbury, to honour the dead. The Lord Mayor of London, Sir Frank Bowater, presided at the Thetis Appeal Fund meeting which at that time stood at £115,000.
From June 3rd to August 24th 1939, Thetis lay at the bottom of Liverpool bay. Almost three months of various attempts to raise her from the sea floor. The cruellest twist of fate befell salvage diver Petty Officer Henry Otho Perdue. Diving from the salvage ship Tedworth with Petty Officer Dick Harknett, Perdue's guide rope snagged on Thetis holding him down. After struggling for some minutes it came inexplicably loose and Perdue raced toward the surface. At 8.25pm on 23rd August 1939 he died from the "Bends". Thetis had claimed her 100th soul.
Thetis was raised to the surface on September 2nd, 12 weeks since she was last seen above the water. She was towed toward the island of Anglesey - point of destination, Moelfre Bay, but Thetis beached on a sand bank where she remained for 8 days until the weather broke.
On September 10th, Thetis returned to land at Moelfre, chosen for its secluded, well sheltered terrain. In a final cruel twist of fate, the weather turned and it took 68 days (work could only be carried out on 21 of these due to the weather) for Thetis to finally release all of her crew. Most are buried in a mass grave at Holyhead.
On November 18, 1939, Job No 1027 returned to the place of her birth.............
His Majesties Submarine Thunderbolt
The men who lost their lives aboard HMS Thetis / Thunderbolt
Last updated by D Cohen 2 January 2002