Slave ships, built for the Middle Passage, were vessels designed to transport slaves from Africa to the New World. It is estimated that around fifteen million Africans were transported to the Americas between 1540 and 1850, each voyage taking two to six months to complete.
Slaves were considered to be cargo by their captors and kept in horrifying conditions aboard, threatening even the lives of the vessel's crew. Captains of these slave ships preferred to carry as much cargo as possible, a vessel of one hundred tons carrying between two hundred and twenty to two hundred and fifty slaves per voyage.
The death rate on these ships was extremely high due to dystentery, fevers, filthy conditions, and other unpredictable diseases brought on board.
There were usually three lodging rooms below deck, some barely five feet high, leaving only about seven square feet of room per slave. Slaves were made to lie down in two rows, one on top of the other, like books on a shelf, usually without room to cram one more in. Slaves could suffocate and trample each other to death, as they tried to claw their way to the surface of the ship.
Known rebellions were recorded on more than three hundred voyages leaving Africa, but measures were taken to scare the slaves into submission. Some commanders threatened the slaves by severing the limbs of rebels to serve as an example of their power.
When slavery was eventually outlawed, slave ships attempted quicker forms of transport to avoid capture and continue their illegal activites.