Eight-year-old Simon Crowhurst huddled in a big, strange bed, listening to the waves batter the coastline while the wind moaned outside his window. His family was staying in a hotel in Teignmouth, on the southern toe of England, because tomorrow his father, Donald, was setting off to sail around the world. But as Simon listened to the weather rage, the excitement he’d felt over his father becoming a real-life adventure hero collapsed. He had seen his father’s spindly 12-metre boat, and for the first time, it occurred to him that this voyage was dangerous. Simon was terrified.

In a nearby room, Donald Crowhurst’s confidence was crumbling into tearful panic as he confessed to his wife, Clare, that his boat wasn’t ready. Only later would it occur to her that he may have been begging her to tell him not to go, to give him a way out. The thought would haunt her. But at the time, even with her normally ebullient husband sobbing in front of her, she still believed he could do anything and didn’t want him to regret giving up. So Clare did for Crowhurst what she’d been doing for their children, 10-year-old James, seven-year-old Roger, five-year-old Rachel, and Simon: She stuffed her fear down deep and told him everything would be fine.

The next day, Oct. 31, 1968, Simon was relieved to see the weather had calmed. His excitement returned, buoyed by the news cameras and onlookers milling around. He and his family boarded his father’s boat, the Teignmouth Electron–named as a publicity nod to the resort town from which he was sailing and his own struggling electronics business—to say goodbye. Crowhurst kissed each of his children on the forehead and told James and Simon to look after their mother. Simon would always remember the undulating sea beneath his feet as he stood on the deck of another boat with his family, watching his father and the Electron get smaller, then slip over the horizon and disappear.

Donald Crowhurst, 36, was about to became a British folk hero, the middle-class family man who conquered the seas and captivated the nation. Later, he would be seen as a con man who claimed to have sailed around the globe—despite never having ventured out of the Atlantic. Ultimately, he was revealed to be the victim of a storm in his own head. His family never saw him again after his boat blinked out of sight, and it would take them years to unravel what happened to him; even now, that’s a jagged-edged question they’ve each answered in their own way. The truth about the inventor’s phony voyage can only be guessed based on the evidence he left behind. What is certain is that when Crowhurst sailed from Teignmouth, he was tragically ill-prepared, but had staked so much on the journey that the circumstances carried him away like a riptide.