I'm interested in metrics regarding trans-atlantic trade in the era of the sail.

The specific timespan doesn't matter. The specific cargo also doesn't matter.

I've searched but not found any estimates regarding the tonnage of the materials transported. I'm specifically interested in goods, not people (free or enslaved), and the corresponding timespan for those metrics, or per-shipment.

E.g. [x] tons of consumer goods were transported across the northern trade winds per [y] timeframe. or The typical ship in 1649 carried [x] volume of goods, and there were an average of [y] shipments per [z].

  • 8
    Please realize that, when discussing the triangle trade, it is .... questionable and confusing to state both that "specific cargo... doesn't matter", and "not people" - the triangle trade was intrinsically about people. I'm uncomfortable with this question.
    – MCW
    Jul 30 '18 at 10:41
  • 2
    So you are asking about the average capacity of the average ship shipping average goods (minus the one good that the term "Triangle Trade" usually is defined by), in a time period spanning roughly three centuries... do you realize how many variables you want to get "averaged" here?
    – DevSolar
    Jul 30 '18 at 11:47
  • 4
    FWIW, I went to WP: Slave Ship and clicked five of the listed ships at random, finding sizes from 110 tons bm to 300 tons bm... and that was by no means a representative selection.
    – DevSolar
    Jul 30 '18 at 12:02
  • 3
    You are tossing variables out of the window with frightening abandon. One thing that distinguishes a slave ship from a bulk freighter, for example, is the necessity for decks. You can't stack slaves, nor can you just pour them in the hold... and when you have decks, you can't just toss sacks of grain into the hold for the "other" leg the way you could with a bulk freighter. Also, slave ships needed to calculate speed vs. slave mortality. A bulk freighter carrying non-perishable goods could take many more weeks underway than a slave ship could afford. Speed and capacity don't match well.
    – DevSolar
    Jul 30 '18 at 12:31
  • 5
    You may find some difficulty in obtaining representative figures here. Contrary to the popular picture of the Triangle Trade, many ships involved in the British slave trade actually returned to the UK 'in ballast' rather than transporting sugar or consumer goods. Other vessels transported those goods. The paper The Commercial and Financial Organization of the British Slave Trade, 1750-1807 includes some references to primary sources which you might find helpful. Jul 30 '18 at 14:44

What was the tonnage carried in the Triangle Trade?
I'm interested in metrics regarding trans-atlantic trade in the era of the sail. The specific timespan doesn't matter. The specific cargo also doesn't matter.

Since you are asking for metrics, I'm not going to comment much in my answer and just give you the metrics I found.

The Middle Passage 1600 - 1800

From PBS The African Slave Trade and the Middle Passage

  • Out of the roughly 20 million who were taken from their homes and sold into slavery, half didn't complete the journey to the African coast
  • 10 to 12 million Africans were sold into slavery from the 15th through the 19th Centuries..
  • Roughly 54,000 voyages were made by Europeans to buy and sell slaves (Middle Passage).
  • Over the centuries, between one and two million persons died in the crossing.


From Digital History The Middle Passage

  • The trans-Atlantic slave trade was the largest movement of people in history.
  • The level of slave exports to the New World grew from about 36,000 a year in the early eighteenth century to almost 80,000 a year during the 1780s. By 1750, slavers usually contained at least 400 slaves, with some carrying more than 700.


Middle Passage Throughout the height of the Atlantic slave trade (1570–1808), slave ships were normally smaller than traditional cargo ships, with most slave ships weighing between 150 and 250 tons. This equated to about 350 to 450 enslaved Africans on each slave ship, or 1.5 to 2.4 per ton. The English ships of the time normally fell on the larger side of this spectrum and the French on the smaller side. Ships purposely designed to be smaller and more maneuverable were meant to navigate the African coastal rivers into farther inland ports; these ships therefore increased the effects of the slave trade on Africa. Additionally, the ships' sizes increased slightly throughout the 1700s; however the number of enslaved Africans per ship remained the same. This reduction in the ratio of enslaved Africans to ship tonnage was designed to increase the amount of space per person and thus improve the survival chances of everyone on board.

The bolded ratio above allows you to convert ship tonnage to yield estimated cargo. The below tables detail date ranges, ship sorties and ship tonnage for vessels involved in the middle passage.

The following tables come from JSTOR
(You need an account to download but can register and view limited number of articles for free)
Characteristics of British Slaving Vessels, 1698-1775

Walter E. Minchinton
The Journal of Interdisciplinary History
Vol. 20, No. 1 (Summer, 1989), pp. 53-81

(*) Some people also forget, before the American Revolution all thirteen colony's permitted slaves. That slavery was mandated by the British as the sale of slaves was a major economic factor in the British Empire in the 1700s. It was one of the objections to the British Empire layed out in the American Declaration of Independence.

He has waged cruel war against human nature itself, violating its most sacred rights of life and liberty in the persons of a distant people who never offended him, captivating and carrying them into slavery in another hemisphere or to incur miserable death in their transportation thither.

Table 1 Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 Table 9 Table 10 Table 11 Table 12 Table 13 Table 14 Table 15 Table 16

  • The liberation of of content is pretty much appreciated and might be valuable on its own. But that many tables as poor resolution graphics is somehow less than ideal. I know the limitations of H:SE for tables and the like. Can you somehow still avoid the commentary but provide… hm, a summary or whatnot (given the awful timeframe of Q that's asking much, but still: tables as graphics=yucks)? Aug 10 '18 at 18:36

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