For several hundred years, European merchants, African warlords, and New World plantation owners participated in a three point trading system whose second leg sent African slaves from the Dark Continent to plantations in the New World. The horrors these slaves faced during this Middle Passage are difficult for the modern mind to comprehend. Millions died along the way. Perhaps they were the lucky ones because the rest had nothing to look forward to besides a lifetime of bondage in the Americas.
Slavery was just one of the important aspects of the Triangle of Trade system that flourished during the 16th and 17th centuries. Typically, ships left European ports with finished goods to trade for slaves in Africa. Those same ships would then journey to the New World were they would exchange their cargo of slaves for raw materials which they then took back to Europe. After those raw materials were made into finished products, the cycle would continue with those finished products again leaving for Africa.
The merchants profited at every stage of the triangle as did those trading with them. Plantation owners got slaves to work their fields, European manufactures got markets for their goods, and African warlords got alcohol, guns, and other things they needed to secure their power over neighboring tribes and ensure that they could provide the European merchants with more slaves. While this description of the Triangle may be a bit simplistic and there was certainly much trade that did not fit this pattern, it was a fairly common way of trading at the time.
One would think that merchants would want to make sure that as many slaves survived the Middle Passage as possible and to a certain extent they did. If a slave tried to commit suicide or starve himself to death, he might be tortured or force-fed to ensure that he did not succeed in his attempts. At the same time, however, the merchants considered the slaves their cargo. Therefore, they treated the slaves only as well as was profitable using a cost/benefit analysis. If it was more profitable to let a few of the slaves starve than to provide all of the slaves with more food, they simply allowed the few to starve.
The conditions aboard the slave ships were atrocious. Slaves were packed together with barely any room to move. Often, the ceiling of the deck they were on was less than five feet tall. In some cases, it was as low as three feet tall. The slaves were given very little food and water and often had to sleep and eat in their own waste because the slavers did not even provide enough room for waste accommodation. Unsurprisingly, disease spread rapidly in such an environment and many died. Although it is impossible to say with any certainty how many died, it is estimated that as many as 10% to 20% of the several million slaves who passed through the Middle Passage died along the way.
As could be expected, the Middle Passage had a demoralizing effect on all of the slaves who experienced it. The slaves had no idea where they were going or how much longer they would live. Most of them had recently lost all of their friends and families and those who had not had to deal with the fact that their loved ones were also slaves, or perhaps had died along the way. If one reason for the horrible conditions was to break down the will of the slaves and in this the Middle Passage must have been a great success. By treating the slaves as animals, the slavers ensured that the slaves would be less willing to organize and resist their captivity.