This is how Africans were shipped as cargo aboard ships

Slave ships were large cargo ships specially converted for the purpose of taking slaves, especially newly captured African slaves to the Americas. Living conditions for slaves on these ships was awful. Men, women and children were crowded into every possible space, leaving no room to move or even breathe. There was little food and the smell could not be described. Between 1526 and 1867 about 12.5 million slaves were sent by slave ships from Africa to the Americas. But only about 10.7 million slaves actually arrived. Of all human migrations it caused the most human deaths. The average time to sail across the Atlantic was 60 to 90 days. Sometimes the trips took up to four months.