Still, when he reached the bow, Jack hesitated. The foremast was taller than a church steeple, and pitching wildly in the storm. Jack’s fingers, already numb with cold, couldn’t even feel the rigging and his sodden clothes had become cumbersome and heavy. The problem was that the longer he stalled, the colder he would get and soon his limbs would be too stiff to save himself.

Come on, he willed himself. You’re braver than this.

Deep down, though, he knew he wasn’t. In fact, he was truly terrified. During the lengthy voyage from England to the Spice Islands, he had acquired a reputation for being one of the best rigging monkeys. But his ability to climb the mast, repair the sails and untangle ‘fouled’ ropes at great height hadn’t come from confidence or skill – it was born out of pure fear.

Jack looked up into the storm. The sky had been whipped into a frenzy and dark thunderous clouds streaked across a colourless moon. In the gloom, he could just make out Ginsel and the rest of the crew in the shrouds. The mast swayed so violently, the men swung like apples being shaken from a tree.

‘Don’t be afraid of storms in life,’ he recalled his father saying, on the day Jack had been tasked with climbing to the crow’s-nest for the first time. ‘We must all learn how to sail our own ship, in any weather.’

Jack remembered how he had watched all the new recruits attempt the terrifying ascent. Every one of them, bar none, had either frozen with fear, or else puked their guts out on to the sailors below. By the time it was Jack’s turn, the wind had got up so much the rigging was rattling almost as fretfully as his own legs.

Jack looked to his father, who squeezed his shoulders with loving reassurance. ‘I believe in you, son. You can do this.’

Convinced by his father’s faith in him, Jack launched himself at the rigging and didn’t look down until he had hauled himself over the lip and into the safety of the crow’s-nest. Exhausted but elated, Jack had let out a yell of delight to his father, tiny as an ant, on the distant deck below. Fear had driven Jack all the way to the top. Getting down had proved another matter…

Jack grabbed hold of the rigging and pulled himself aloft. He quickly fell into his usual rhythm, the comfort of habit providing some reassurance. Hand over hand, he rapidly gained height, until he could see the white crests of the waves as they charged at the ship. But they were no longer the threat. It was the relentless wind. Fearsome gusts did their utmost to drag Jack off into the night, but instinctively bracing himself he continued upward. Before long he was standing next to Ginsel on the yardarm.

‘Jack!’ yelled Ginsel, who looked worn out, his eyes bloodshot and sunken. ‘One of the halyards got fouled up. The sail won’t drop. You’re going to have to go out there and unsnag it.’