Murphy’s Law in Action

What this episode is about

The narrative centers on the harrowing realities of submarine service, particularly exemplified by the tragic 1939 incident involving the British submarine HMS Thetus, which faced unforeseen mechanical failures during a routine test dive. It highlights the perilous nature of submarines, where mishaps can lead to catastrophic outcomes even in peacetime, underscoring the principle of Murphy's Law—anything that can go wrong, will go wrong—in the context of military operations under challenging conditions.

Key takeaways

• Submariners dance with death daily; even peace can be dangerous in a metal tube underwater.
• HMS Thetus shows that when machines meet human error, even top-notch technology can lead to tragedy.
• Oxygen toxicity: the underwater killer that turns lifesaving gear into a crew's worst nightmare below 5m.
• Murphy's Law: submarines at sea; even the smallest mechanical issue can spell disaster in deep water.
• Think you can escape? The tyranny of pressure and malfunction rests heavy as Thetus descends into darkness.

Who speaks in this episode?

• Guy Bolas · 1 min speaking
• Frederick Woods · 1 min speaking
• Herbert Chapman · 1 min speaking
• Harry Orum · 1 min speaking

What is discussed, and when

1. 0:00 – 3:00: Guy Bolas, Frederick Woods
2. 3:00 – 6:00: Frederick Woods, Herbert Chapman
3. 6:00 – 9:00: Herbert Chapman, Harry Orum, Cha Buren
4. 9:00 – 11:01: Frederick Woods

Notable quotes from "Murphy’s Law in Action"

• Royal Navy technical observers and workmen from Camel Lead, the submarine's builder. At around 2 p.m., Commander Bolas ordered the Thetus to make its first dive. However, even…

  about Guy Bolas · at 1:07

• The first to volunteer was first left tenant Herbert Chapman, but soon after the chamber began to flood, he banged on the hatch in distress and had to be let out. Not only had the water pressure.

  about Herbert Chapman · at 4:05

• Decided to send out two men with messages tied to their wrists explaining the situation. Lieutenant Woods and the submarine's captain Harry Orum volunteered and using the…

  about Harry Orum · at 6:31

• 100th victim, salvage diver Henry Perdu who died of the bends during the recovery attempt. The wreck was finally refloated and beached at Cha Buren in Wales on September 1st…

  about Cha Buren · at 8:36

Who and what is mentioned in this episode?

People

• Guy Bolas — Person · Referenced commander (commanding officer) of HMS Thetis during trials · 1 mention · first at 1:02
  He commands the shakedown dive, directs emergency actions (buoys/flares, pumping fluids), and makes key decisions about escape timing and rescue strategy.
• Frederick Woods — Person · Referenced officer (torpedo officer) involved in HMS Thetis accident · 3 mentions · first at 1:25
  Central participant in the chain of events: he checks torpedo tubes/bow caps and later escapes to the surface to report the situation.
  To sink. Suspecting that some of the empty torpedo tubes were still filled with air, bowlers ordered torpedo officer Latutenant Frederick Woods to ensure that they were all…
• Herbert Chapman — Person · Referenced officer (escape attempt volunteer) during HMS Thetis sinking · 3 mentions · first at 4:05
  His failed escape-chamber attempt illustrates the dangers of oxygen toxicity with the Davis apparatus at depth; later he is involved in further escape-chamber actions described in the narrative.
• Harry Orum — Person · Referenced captain who escapes to surface with message · 1 mention · first at 6:35
  He and Woods successfully use the escape chamber to reach the surface and communicate the submarine's condition to rescuers, marking a pivotal moment in the rescue attempt.

Places & events

• Cha Buren — Place · 1 mention · first at 8:41

Full transcript with timestamps

0:00 It has been called the silent service since their introduction in the early 20th century. Service aboard submarines has been among the deadliest military occupations with a full 70% of German yubo crews during World War II never returning from patrol. But the hazards faced by submariners go well beyond enemy guns, depth charges, and torpedoes. Submarines are complex machines operating in an extremely hostile environment and can prove just as deadly in peace time as in war. So the crew of the British submarine HMS Thetus was to discover in June 1939 when a seemingly routine shakedown cruise ended in a tragic accident where Murphy's law was proven to be an immutable rule of the universe. By the way, if you've not seen our video on who was the Murphy and Murphy's law, we strongly suggest you go watch it. In any event, HMS Thetus, the second T-class submarine to be laid down, was launched on June the 28th, 1938. Initial trials

0:50 revealed mechanical problems with her forward diving planes, causing sea trials to be delayed until the next summer. On June the 1st, 1939, Thetus accompanied by the civilian tiger boat Grebok, sailed into Liverpool Bay under the command of left tenant commander Guy Bolas. Aboard were 103 men, including 44 Royal Navy technical observers and workmen from Camel Lead, the submarine's builder. At around 2 p.m., Commander Bolas ordered the Thetus to make its first dive. However, even after the forward ballast tanks were flooded, the bow of the submarine stubbornly refused to sink. Suspecting that some of the empty torpedo tubes were still filled with air, bowlers ordered torpedo officer Latutenant Frederick Woods to ensure that they were all flooded. Woods opened a small test on each torpedo tube and found that all of them were dry. He then checked to see if the bow caps at the other end of the tubes were

1:37 all closed. However, the bow cap indicators were obscured behind a piece of hull structure. So Woods instead looked at the bow cap handles, all pointing vertically, indicating that the caps were shut. Woods thus ordered leading seaman Ham to open the rear torpedo tube hatches one by one. The locking tube on number five proved unusually stiff, but Hamch eventually managed to wrench it open. Then all hell broke loose. As soon as the handle was turned, the hatch blew open and the sea came roaring in. As the torpedo room flooded, Thetus suddenly pitched down and began to sink by the bow. Unable to close the torpedo tube hatch woods and the torpedo crew retreated after into the next compartment. It attempted to seal off the torpedo room, but the angle of the boat made closing the wateride hatches, which opened a full 180° impossible. The crew thus retreated again and finally managed to seal off

2:22 the torpedo stowage compartment. But by this time, Thetus had taken on so much water that it nosed and struck the seabed 150 ft below, embedding the bow in the mud. In desperation, the crew tried blowing all of the ballast tanks but to no avail. The flooded compartments were simply too heavy. Following emergency procedure, Commander Bolas ordered the deployment of the submarine's emergency boys and signal flares, but the cable on the aft boy wrapped itself around the boat's stern while that on the forward boy snapped causing it to drift away in the current.

2:50 Not that either would have helped the thetus, as the submarine had planned to make a three-hour test drive, the crew of the Grabacco was initially unaware that anything was a miss. For the moment at least,, the, crew, of, the, Thetus, were, on their own. With the air in the submarine growing swiftly toxic with carbon dioxide from the men's breath, one of the crew hatched a daring plan. The T-class was among the first British submarines to be fitted with escape chambers to allow the crew to bail out in an emergency. These were used in combination with the newly introduced Davis submerged escape apparatus or DSEA, a combination breathing device and life jacket that provided around 30 minutes of oxygen, more than enough to allow a crewman to ascend to the surface. To use the escape chamber, a sailor dawned a Davis set, climbed into the chamber, and closed the inner hatch behind him. He then opened a valve to

3:35 flood the chamber and equalize the pressure before opening the outer hatch and swimming to safety. The outer hatch could then be closed and the chamber pumped dry by another crewman so the process could begin again. Thetus had two escape chambers, one forward and one after mounted in the middle of a bulkhead with two hatches allowing access from either side. According to the plan, a sailor wearing a Davis set would enter the chamber from the dry side, flood the chamber, and then enter the flooded compartment on the other side. He would then close the torpedo tube hatch so both compartments could then be pumped out with compressed air.

4:05 The first to volunteer was first left tenant Herbert Chapman, but soon after the chamber began to flood, he banged on the hatch in distress and had to be let out. Not only had the water pressure caused crippling air pain, but at depths greater than 5 m, the pure oxygen supplied by the Davis set becomes toxic rendering Chapman dizzy and disoriented. Lieutenant Woods, torpedo gunner's mate Mitchell, and Petty Officer Smithers were the next to try. But all three were also overcome by oxygen poisoning, and the plan had to be abandoned. While there was a chance that blowing compressed air into the flooded compartments might clear them, Thetus had only enough compressed air for one attempt. Instead, Commander Bolas ordered the submarine's fuel oil and drinking water pumped overboard lightening the boat enough to allow its stern to protrude above the water. When help arrived, Bolas reasoned recovery

4:48 ships could attach air hoses to the submarine's exterior fittings, providing enough compressed air to blow the forward compartments. This action also brought the after escape chamber close enough to the surface to be safely used without fear of oxygen poisoning. However, Bolas did not want his crew bailing out until rescue ships had arrived, as they would quickly freeze to death in the cold water. Expecting the recovery fleet to arrive sometime the next morning, Bolas and the crew settled down for a long and uneasy night.

5:13 Meanwhile, the rescue operation was only just getting underway. When 3 hours after the sinking, the crew of the Grabacco finally realized something was wrong, they were reluctant to declare a full emergency and instead simply asked the submarine base at Portsmouth when Thetus was expected to surface. However Grammarok's radio transmitter was so old and weak that it couldn't transmit 50 km to Liverpool, and the signal instead had to be relayed by another ship and sent by telegraph to the Portsouth Post Office, where it was carried by bicycle courier to the naval base. But in a stroke of bad luck of the kind that would characterize the whole affair, the messenger's bicycle suffered a flat tire, which he spent an entire halfhour fixing before setting off for Portsmouth. With the alarm at last raised, Royal Air Force aircraft was dispatched to locate the stricken Thetus. Almost immediately, it spotted

5:56 the submarine stern protruding above the waves. But the navigator, anxious to get the position right, requested the aircraft circle again while he recalculated his location. Unfortunately, this second fix turned out to be dead wrong. Such that when the destroyer, HMS Brazen, finally arrived on the scene, it began searching some 12 nautical miles from the thetus' actual position. It was not until around 7:00 a.m. the next morning that the Brazen finally spotted the submarine stern and dropped signal grenades to announce its arrival. Aboard the Thetus, the situation was becoming dire. The crew halfconscious as they slowly succumbed to carbon dioxide poisoning. On hearing the brazen's arrival, Commander Bolas decided to send out two men with messages tied to their wrists explaining the situation. Lieutenant Woods and the submarine's captain Harry Orum volunteered and using the escape chamber

6:41 made a successful ascent to the surface where they were picked up by Raisen's whaleboats. But then things quickly went from bad to worse. In their rush to drain the chamber and send out another pair of men, the crew opens the hatch prematurely and let a lot of water spill out. This shorted an electrical panel and started a small fire which burned up much of the remaining oxygen. Realizing that the end was near, Lieutenant Chapman packed four men, Stoker's Canyon hole and two camel layered fitters into the chamber and closed the hatch behind them. 20 minutes later, certain that they had made it out, Chapman drained the chamber and opened the hatch. To his horror, the dead bodies of the four men flopped out. suffering from oxygen poisoning. They had been unable to open the outer hatch and drowned when their Davis sets ran out. The bodies were stowed out of sight and further escape attempts were suspended. Back on the

7:26 surface, chaos reigned. Though a small flotilla of Navy and civilian ships had gathered around the thetus, which bobbed tantalizingly within reach, all were powerless to do anything, as none had any divers or submarine rescue experts on board. A plan to cut holes in the theaters's stern to let in breathing air was quickly proposed, but quickly abandoned as it risked further flooding the submarine. Then at 10:00 a.m. stunned on Looker saw a pair of heads pop to the surface. They were leading stoker Walter Arnold and camel lay fitter Frank Shaw, who had just made another successful ascent using the escape chamber. Tragically, these would be the last survivors of the HMS thetus.

8:00 Disorientated by carbon monoxide poisoning, Lieutenant Chapman had failed to release the gearing on the chamber hatch. And when the next two men tried to escape, the hatch only opened a few inches, and both died of oxygen poisoning before the chamber could be drained. Then at around 2:45 p.m., the end finally came. While attempting to use the escape chamber, one of the crew accidentally left both the chamber hatch and flooding valve open, causing the submarine to flood. As the rising water displaced air, and the carbon monoxide levels skyrocketed, the crew slipped into comas as the thetus slipped beneath the waves and settled on the sea floor taking 99 men with her. It took nearly 3 months to salvage the thetus, during which time the submarine claimed its 100th victim, salvage diver Henry Perdu who died of the bends during the recovery attempt. The wreck was finally refloated and beached at Cha Buren in

8:45 Wales on September 1st, 1939, the day the Second World War broke out. HMS Thetus was repaired and recommissioned in 1940 as HMS Thunderbolt, which served with distinction before being sunk with all hands off Sicily on March the 14th 1943. But what in the end caused HMS Thetus to sink? How had the torpedo bow cap actually been open when all indications pointed to it being closed? The Royal Navy's investigation revealed a series of flaws in the submarine's design which made it extremely difficult for Lieutenant Woods to assess the condition of the torpedo tubes. In addition to being obscured by the submarine structure, the six bow cap indicators were arranged vertically in a confusing order with the bottom indicator corresponding not to tube number six, but rather to tube number five. And while the bow cap levers on earlier submarines had only two positions, open and closed, those on Thetus had three: Open, closed, and

9:35 neutral. With the handles being returned to the neutral position after each operation, it was thus impossible to tell from the position of the handles whether the bow caps were open or closed. Yet, despite all this, the test should, have, provided, the, final, line of defense against opening a flooded torpedo tube. But in a minor but ultimately fatal oversight during the submarine's construction, a painter had failed to mask the test and the tiny holes were covered over with paint. A pricking tool had been provided to clear debris from the holes. But as the boat was brand new, Lieutenant Woods decided that this was unnecessary with tragic results. The sinking of the HMS Thetus laid bare the serious organizational shortcomings of the pre-war Royal Navy and dramatically illustrated how a combination of bad design, poor training, and bad luck can lead to a disaster. It was a textbook example of how for a major disaster to

10:22 occur, many different things must go wrong simultaneously. Had the torpedo room been better designed, had Lieutenant Woods thought to clear the test had the Graco raised the alarm sooner, had the spotter aircraft not incorrectly reported Thetus' position, had any of the individual links in the chain of disaster been broken, the loss of life might have been considerably lower. But in the end, as the old saying goes, for the want of a nail, a submarine was lost. So, I really hope you found that video interesting. If you did, please do hit that thumbs up button below. Don't forget to subscribe and thank you for watching.

Questions about this episode

Who speaks in "Murphy’s Law in Action"?

Guy Bolas, Frederick Woods, Herbert Chapman, Harry Orum.

What is "Murphy’s Law in Action" about?

The narrative centers on the harrowing realities of submarine service, particularly exemplified by the tragic 1939 incident involving the British submarine HMS Thetus, which faced unforeseen mechanical failures during a routine test dive. It highlights the perilous nature of submarines, where mishaps can lead to catastrophic outcomes even in peacetime, underscoring the principle of Murphy's…

What is mentioned in this Today I Found Out episode?

5 people, works and ideas are mentioned, including Guy Bolas, Frederick Woods, Herbert Chapman, Harry Orum, Cha Buren. Each one on this page links to its own page with every episode that mentions it.

How long is "Murphy’s Law in Action"?

The episode runs 11 min; the transcript is about 2,244 words in 16 timestamped sections.

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