19th century – 19th century
West African coast and Atlantic waters
A prolonged nineteenth-century campaign by British, French, American, Dutch, and Portuguese naval forces to intercept slave ships and restrict the Atlantic trade from the West African coast. It combined patrols, captures, mixed commissions, blockades, treaties with coastal rulers, and armed expeditions, but remained limited by weak enforcement, diplomatic rivalry, poor vessels, false flags, and the protection afforded by American sovereignty until 1862.
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The Story
Naval suppression on the West African coast developed unevenly after abolitionist measures were adopted in Europe and the Americas. Dutch, Portuguese, and American squadrons operated intermittently, while the American force was based at Cape Verde, far from the principal centres of traffic. The British and French were the only powers maintaining continuous operations, yet their stated commitments often exceeded their practical presence along the coast.
France established a squadron in 1818, based at Gorée, but its first four years produced no suppressive action because the government’s intentions were uncertain. A bounty introduced in 1825 encouraged seizures, and the number of French vessels later increased from three to six by 1838, reaching fourteen on each side in 1843–44. In 1845, amended Anglo-French treaties fixed twenty-six ships for each party, creating the appearance of a substantial international task force when combined with American and Portuguese vessels.
The British Admiralty expanded its force from three warships to twenty-six, but the vessels were poorly suited to the task. Their draught prevented them from sailing far up rivers, their boats were exposed to attacks from slave-trading stations, and their slow sailing qualities allowed lighter slave ships to escape. British crews nevertheless conducted searches and seizures, sometimes before treaties authorized them, while capture bounties and high mortality among captured Africans exposed the contradictions within humanitarian policing.
Slave ships exploited the confusion of international enforcement by using false flags and forged papers, evading cruisers perhaps four times out of five. As treaties strengthened, French papers ceased to protect vessels after 1831 and Portuguese papers after 1842, but American sovereignty continued to shield slave trading under the United States flag until 1862. Enforcement therefore depended as much on diplomatic arrangements and local political conditions as on naval strength.
Cruisers and colonial governors increasingly organized overland punitive expeditions against trading stations and coastal settlements. In Liberia, Governor Jehudi Ashmun moved against stations at Cape Mount; near Sierra Leone, Governor Turner’s 1825 campaign temporarily cleared the islands and peninsula and placed a long stretch of coast under permanent British tutelage. Similar operations reached the Gallinas, Sherbro, and Rio Pongos, while slave ships in Portuguese waters near Cabinda and Ambriz were shelled and barracoons were burned.
The decade 1841–50 marked a decisive shift on the western coast. Treaties with local rulers sought to suppress the trade within their territories, although some agreements were imposed rather than negotiated. Standing blockades of major export centres introduced a policy of diplomacy backed by armed intervention, extending naval suppression beyond interception at sea and drawing African political authorities directly into the enforcement system.
19th century – 19th century
West African coast and Atlantic waters
A prolonged nineteenth-century campaign by British, French, American, Dutch, and Portuguese naval forces to intercept slave ships and restrict the Atlantic trade from the West African coast. It combined patrols, captures, mixed commissions, blockades, treaties with coastal rulers, and armed expeditions, but remained limited by weak enforcement, diplomatic rivalry, poor vessels, false flags, and the protection afforded by American sovereignty until 1862.
Continue exploring
The Story
Naval suppression on the West African coast developed unevenly after abolitionist measures were adopted in Europe and the Americas. Dutch, Portuguese, and American squadrons operated intermittently, while the American force was based at Cape Verde, far from the principal centres of traffic. The British and French were the only powers maintaining continuous operations, yet their stated commitments often exceeded their practical presence along the coast.
France established a squadron in 1818, based at Gorée, but its first four years produced no suppressive action because the government’s intentions were uncertain. A bounty introduced in 1825 encouraged seizures, and the number of French vessels later increased from three to six by 1838, reaching fourteen on each side in 1843–44. In 1845, amended Anglo-French treaties fixed twenty-six ships for each party, creating the appearance of a substantial international task force when combined with American and Portuguese vessels.
The British Admiralty expanded its force from three warships to twenty-six, but the vessels were poorly suited to the task. Their draught prevented them from sailing far up rivers, their boats were exposed to attacks from slave-trading stations, and their slow sailing qualities allowed lighter slave ships to escape. British crews nevertheless conducted searches and seizures, sometimes before treaties authorized them, while capture bounties and high mortality among captured Africans exposed the contradictions within humanitarian policing.
Slave ships exploited the confusion of international enforcement by using false flags and forged papers, evading cruisers perhaps four times out of five. As treaties strengthened, French papers ceased to protect vessels after 1831 and Portuguese papers after 1842, but American sovereignty continued to shield slave trading under the United States flag until 1862. Enforcement therefore depended as much on diplomatic arrangements and local political conditions as on naval strength.
Cruisers and colonial governors increasingly organized overland punitive expeditions against trading stations and coastal settlements. In Liberia, Governor Jehudi Ashmun moved against stations at Cape Mount; near Sierra Leone, Governor Turner’s 1825 campaign temporarily cleared the islands and peninsula and placed a long stretch of coast under permanent British tutelage. Similar operations reached the Gallinas, Sherbro, and Rio Pongos, while slave ships in Portuguese waters near Cabinda and Ambriz were shelled and barracoons were burned.
The decade 1841–50 marked a decisive shift on the western coast. Treaties with local rulers sought to suppress the trade within their territories, although some agreements were imposed rather than negotiated. Standing blockades of major export centres introduced a policy of diplomacy backed by armed intervention, extending naval suppression beyond interception at sea and drawing African political authorities directly into the enforcement system.