As the main boom swept across the deck, Captain James Riley heard a roaring sound that stopped him cold. Thinking it was a squall approaching unseen in the dark, he shouted, "All hands on deck!" and ordered his second mate, Aaron Savage, to brace up the yards. As the men hauled the lines, the square sails spilled the wind, checking the brig's speed. Riley was about to order the sails lowered when he saw foam billowing on the lee side of the brig. He had been wrong. The roar was not a squall. It was something even worse: the sound of breakers.

The Commerce, a 220-ton brig out of Middletown, Connecticut, had recently unloaded her cargo of flour and tobacco in Gibraltar. Now she was skirting the treacherous northwest coast of Africa to the Cape Verde Islands, where she was to take on a load of salt to sell at home. Sailing into fog on the night of August 28, 1815, Riley had assumed his ship was passing by the Canary Islands, some 60 miles (97 kilometers) off the coast. But he had a gnawing feeling that something wasn't right. Now, the sound of the Atlantic rollers pounding the shore to his lee told him he'd made a disastrous error in navigation.

Riley kept his head, barking out new commands. The crew cleared away the 1,400-pound (634-kilogram) iron-and-wood anchors on either bow. Before he could order them to be dropped, however, a ghastly jolt hurled the sailors to the deck. Every man knew instantly that his worst nightmare—the violent end that had stalked him all of his working life, waiting for his vigilance to slacken or his luck to sour—had finally come to pass; only instead of going to the bottom, the bottom had come to them. The surf rammed the Commerce onto the rocks and swept across her decks. Each deluge sent the men sprawling or scurrying for a handhold to keep from being washed overboard.

The sweet new brig that Riley's uncle had entrusted to him was doomed. Now Riley, a father of five, could only hope to save himself and his men. Among his crew of 11, second mate Aaron Savage, able seaman Archie Robbins, both in their early 20s, and the cabin boy Horace Savage, 15, all of old Puritan stock, were practically like sons to Riley. Horace's father, a sailor in the West Indies trade like most Lower Connecticut Valley watermen, had been Riley's best friend, until he himself was lost at sea.

Although Riley still had not seen land and had no idea how close they were, he prepared to abandon ship. He ordered the crew to bring provisions up from the hold and to make the longboat ready for launching. At around midnight, as the brig settled and the waves broke with increasing strength over the deck, Riley studied the horizon around them in the faint light of a quarter moon. At last, he made out the coast.

For centuries Cape Bojador has been known as one of the navigable world's most treacherous places. The British Royal Navy's Africa Pilot, warns that the charting of this coast is "reported to be inaccurate" to this day. The cape lies at the base of a narrow strait, where the Canary Islands form a funnel that squeezes the south-flowing current hard against the Moroccan coast in a frenzy of wind, whitecaps, and fatal shoals. There the Sahara abuts the sea in a mutable front of dun-colored cliffs and shifting walls of sand. The cape's rocky beaches collect ships the way a spider's web traps flies.

To an American sailor of 1815, the vast desert region beyond those bluffs was as alien and unexplored as Antarctica. Mariners knew that shipwrecked Christian sailors who refused to disarm on this coast were treated brutally by the Arabs and often slaughtered to the man, and some believed that the inhabitants were cannibals. The prospect of wrecking on this hostile shore had left strong men utterly undone. In 1784, when the French ship Les Deux Amies grounded near Cape Blanco, its captain became so distraught that he tried to blow up the ship's powder magazine. When stopped, he put two bullets in his throat.

Riley gave vent to no such fears. But the wreck of the Commerce would be the beginning of an ordeal that he would barely survive, and many of his crew would not. Ahead of them lay almost unimaginable trials: hunger and thirst, brutal captivity at the hands of desert nomads, and, for the lucky ones, an epic 800-mile (1,287-kilometer) trek across the Sahara to freedom.

Online Extra
Q&A: Enslaved in the Sahara
The story is gruesome (five men met their end in the Sahara) and hopeful (another seven survived). Dean King talks about the remarkable story of Captain James Riley and the crew of the Commerce in our online Q&A >>