26 people died after getting trapped in submarine in one of the most 'unimaginable' deaths of all time

Here is the devastating story of how 26 people lost their lives after getting trapped underwater in a horrifying submarine disaster.

Nowadays, when someone brings up the topic of submarine deaths, most people will think of 2023's Titan submersible, which was a rare and tragic freak accident of modern times.

However, working underwater used to be particularly dangerous, with many sailors dying on submarines in during World War One. This happened so often that in the following years, the US Navy nicknamed it 'the coffin service'.

One of the submarines which suffered this dreaded fate was the USS Squalus.

The Isles of Shoals, close to the location where the USS Squalus embarked on its fateful test (Getty Stock Images)

The story of USS Squalus

One of the most advanced subs around at the time, the USS Squalus could dive up to 250 feet underwater and travel up to 11,000 miles without needing to refuel. It was also capable of submerging in just 60 seconds at full speed.

The latter is exactly was the crew onboard were testing on the fateful day of 23 May.

A total of 59 men where onboard, including captain Lieutenant Oliver Naquin as well as two navy engineers and a representative from General Motors to conduct the test.

The sub was loca5ed off the coast near between the states of New Hampshire and Maine, beginning smoothly as it sunk beneath the waves. However, things would take a turn after Naquin felt his ears pop, signalling a change in air pressure.

At the same time, a desperate plea would be heard over the radio informing crew that the submarine's engine room was flooding.

A depiction of the USS Squalus rescue published at the time (Bridgeman via Getty Images)

This message would leave the captain baffled, as moments earlier, the control room lights had turned green - signalling that all hull openings were closed.

Naquin would attempt to resurface the submarine by blowing ballast tanks (an emergency technique which allows the sub to rise).

However, the ship would plunge downwards at a 45-degree angle.

The watertight doors were sealed, dooming all of the men in the rear of the ship. Nine men perished in the engine rooms, and a further 17 men would die attempting to seal themselves in the torpedo room at the sub's tail.

Back in the control room, the survivors were not out of the woods either, as the submarine's batteries had been exposed to water, meaning an explosion was imminent. Surviving engineer Lawrence Gainer was heroically able to shut off the electrics, losing half of his vision in the process.

The US Falcon and diving bell used to rescue the surviving divers (Bettmann/Getty Images)

As the submarine sunk to lower depths, fears of implosion were increased. The Squalus would finally settle at a depth of 240 feet underwater.

The men were underwater for a total of 23 hours before rescue, suffering headaches and nausea from the lack of air supply.

Their rescue involved the use of a revolutionary diving bell, which allowed survivors to be lifted to the surface.

33 men survived the incident, which was ruled as mechanical malfunction, with four of the men later dying in action during WWII.