Slave ships were large cargo ships specially converted for the purpose of transporting slave
A plan of the slave ship Brookes, showing how 454 slaves were accommodated on board. This same ship had reportedly carried as many as 609 people; published by the Society for Effecting the Abolition of the Slave Trade
Only a few decades after the arrival of Europeans to America, demand for unpaid labor to work plantations made slave-trading a profitable business. The peak time of slave ships to the Atlantic passage was between the 18th and early-19th centuries, when large plantations developed in the colonies of America.
In order to achieve profit, the owners of the ships divided their hulls into holds with little headroom, so they could transport as many slaves as possible. Unhygienic conditions, dehydration, dysentery and scurvy led to a high mortality rate, on average 15% and up to a third of captives. Often the ships, also known as Guineamen, transported hundreds of slaves, who were chained tightly to plank beds. For example, the slave ship Henrietta Marie carried about 200 slaves on the long Middle Passage. They were confined to cargo holds with each slave chained with little room to move.
The most significant routes of the slave ships led from the north-western and western coasts of Africa to South America and the south-east coast of what is today the United States, and the Caribbean. As many as 20 million Africans were transported by ship. The transportation of slaves from Africa to America was known as the Middle Passage.
Owners of slave ships did their best to hold as many enslaved people as possible, cramming, chaining, and selective grouping techniques were used to maximize space and make travel more profitable.Those that were on the ships were underfed and treated with brutality which caused some to die before even arriving at their destination. These people also were not treated as human: living like animals throughout their long voyage to the New World. The enslaved were naked and shackled together with several different types of chains, stored on the floor beneath bunks with little to no room to move due to the crammed conditions. They spent a large portion of time pinned to floorboards which would wear skin on their elbows down to the bone.
The speed of slave ships made them attractive ships to repurpose for piracy, and also made them attractive for naval use after capture
the USS Nightingale (1851) and HMS Black Joke (1827) were examples of such vessels
The Slave Trade Act 1788 regulated conditions on board British slave ships for the first time. It was introduced to the United Kingdom parliament by Sir William Dolben, an advocate for the abolition of slavery. For the first time, limits were placed on the number of enslaved people that could be carried. Under the terms of the act, ships could transport 1.67 slaves per ton up to a maximum of 207 tons burthen, after which only one slave per ton could be carried.
The well-known slave ship Brookes was limited to carrying 454 people; it had previously transported as many as 609 enslaved. Olaudah Equiano was among the supporters of the act but it was opposed by some abolitionists, such as William Wilberforce, who feared it would establish the idea that the slave trade simply needed reform and regulation, rather than complete abolition.
This limited reduction in the overcrowding on slave ships may have reduced the on-board death rate but this is disputed by some historians.
The African slave trade was outlawed by the United States of America and the United Kingdom in 1807. The applicable UK act was the Abolition of the Slave Trade Act and outlawed the slave trade throughout the British Empire. The US law took effect on January 1, 1808. After that date all US and British slave ships leaving Africa were legally pirate vessels subject to capture by the United States Navy or Royal Navy. at the Council of Vienna, Spain, Portugal, France, and the Netherlands also agreed to abolish their slave trade.
After abolition, slave ships adopted quicker, more maneuverable forms to evade capture by naval warships, one favorite form being the Baltimore Clipper. Some had hulls fitted with Copper sheathing. This was very expensive work that at this time was only commonly done to Royal Navy vessels. However it increased speed by preventing the growth of marine weed on the hull, which would otherwise cause drag.
The speed of slave ships made them attractive ships to repurpose for piracy, and also made them attractive for naval use after capture; the USS Nightingale (1851) and HMS Black Joke (1827) were examples of such vessels. HMS Black Joke had a notable career in Royal Navy service and was responsible for capturing a number of slave ships and freeing many hundreds of slaves.