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 the full 70% of German U-boat crews during World

War II, never returning from patrol.

But the hazards faced by some mariner 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 peacetime as in war.

So the crew of the British submarine HMS Thetus was to discover in June 1939 when a seemingly

routine shakedown crews 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-Clav submarine, to be laid down, was launched on June 28th, 1938. Initial trials revealed mechanical problems with her forward diving planes, causing sea trials

to be delayed until the next summer.

On June the 1st, 1939, thetetus, accompanied by the civilian tugboat Grebecock, sailed

into Liverpool Bay under the command of Lieutenant Commander Guy Bolus.

Aboard were 103 men, including 44 Royal Navy technical observers and workmen from Canal

Laird, the submarine's builder.

At around 2pm, Commander Bollos 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, Boulos ordered

torpedo officer, Lieutenant

Frederick Woods, to ensure that they were all flooded.

Woods opened a small test cock on each torpedo tube and found that all of them were dry.

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