When RMS Titanic hit an iceberg at about 23:40 BST on 14 April 1912, it was not until an hour later that an emergency call went out to other ships in the area.
The morse code message was picked up by the RMS Carpathia which was on its way to Gibraltar from New York.
It was captained by Arthur Rostron from Bolton.
His story is the subject of a new episode of Hidden Manchester on Sounds.
Dik Barton, from the British Titanic Society, said it was pure luck the Carpathia received the message in the middle of the night.
“It was most extraordinary that the Carpathia radio operator picked it up because other vessels in the proximity – the California, for example – the actual radio operator was asleep at the time,” he said.
Rostron turned his ship around but the Carpathia was still hours away from where the disaster was unfolding.
RMS Titanic, the ship that was labelled as “practically unsinkable,” foundered and went beneath the waves at 02:20 on 15 April.
The Carpathia continued its own dangerous journey, unaware that the Titanic had already sunk.
Rostron pushed the engines to its limit through an iceberg field.