The trip to Puerto Principe usually took three days, but the winds were adverse. Three days out at sea, on June 30, Sengbe used a loose spike he had removed from the deck to unshackle himself and his fellow slaves. They had been whipped and maltreated and, at one point, made to believe that they would be killed for supper on arrival. Sengbe armed himself and the others with cane knives found in the cargo hold. He then led them on deck, where they killed Captain Ferrer and the cook Celestino and wounded the Spaniard Montez. But Sengbe spared Montez' life together with those of Ruiz and Antonio, the cabin boy. The mutineers lost two of their own party, killed by Captain Ferrer. The two white seamen managed to escape from the Amistad in a small boat.

Sengbe then ordered the Spaniards to sail in the direction of the rising of the sun, or eastward towards Africa. At night, however, Montez, who had some experience as a sailor, navigated by the stars and sailed westward, hoping to remain in Cuban waters. But a gale drove the ship northeast along the United States coastline. The schooner followed a zigzag course for two months, during which eight more slaves died of thirst and exposure. Sengbe held command the whole time, forcing the others to conserve food and water, and allotting a full ration only to the four children. He took the smallest portion for himself.