It is well-known that conditions on the ships of the Middle Passage were beyond terrible. The slavers who were carrying the slaves to the New World wanted to get as many slaves on each ship as possible. The voyages took so long that it was important to bring as many slaves as possible so as to make a good profit. For these reasons, and because they did not care very much about the health or welfare of the slaves, the slavers created terrible conditions on their ships.
As the drawing in this link shows, the slaves were packed very closely together in the holds of the ships. They were given very little space between them. Many were chained together. There was typically not enough room in the hold to stand up, and even sitting up was difficult in some slave ships.
A picture of what things were like in these ships can be found in Olaudah Equiano’s famous slave narrative. He talks about how the crowded and hot the holds were. He talks about how there was not enough room to even turn around. He talks about how the tubs into which people relieved themselves were disgustingly smelly. Other accounts tell us that many people could not make it to the tubs and that the tubs often tipped over in rough weather. In short, things were hellish in the holds of slave ships.