Slave ships were often cargo ships which had undergone modification to the space below the deck to accommodate as many slaves as possible. These ships traveled for several months at a time, stopping to buy and sell slaves at multiple locations.
Slave traders often chained the slaves to plank beds, shackled them to the floor and crammed them in so tightly in the area below deck that they were unable to move. Some slave ships kept the women and children in separate quarters from the men. The route known as the Middle Passage is infamous for being the route traveled by numerous slave trade ships between Africa and America.