After the slaver ship reached port at Black River, Jamaica, Zong's owners made a claim to their insurers for the loss of the enslaved Africans.
The jury found for the slavers but at a subsequent appeal hearing the judges, led by Lord Chief Justice, the Earl of Mansfield, ruled against the slave-trading syndicate owners, on the grounds that new evidence suggested that the captain and crew were at fault.
Following the first trial, Olaudah Equiano, a freedman, brought news of the massacre to the attention of the anti-slavery campaigner Granville Sharp, who worked unsuccessfully to have the ship's crew prosecuted for murder.
It operated as a slave ship based in Middelburg, Netherlands, and made a voyage in 1777, delivering enslaved Africans to the Dutch colony of Surinam in South America.
[15] While Collingwood lacked experience in navigation and command, ship's surgeons were typically involved in selecting captured Africans for purchase, so their medical expertise supported the determination of "commodity value" for a captive.
[8] Due to his ineptitude and enmity incurred with John Roberts, governor of the castle, Stubbs was forced out of the governorship of Anomabu by the RAC council after nine months.
[21] Mariners willing to risk disease and rebellions on slave ships were difficult to recruit within Britain and were harder to find for a vessel captured from the Dutch off the coast of Africa.
[27] Stubbs had captained a slave ship several decades earlier and he temporarily commanded Zong during Collingwood's incapacitation but he was not a registered member of the vessel's crew.
[28] According to the historian James Walvin, the breakdown of the command structure on the ship might explain the subsequent navigational errors and the absence of checks on supplies of drinking water.
[29] On 27 or 28 November, the crew sighted Jamaica at a distance of 27 nautical miles (50 km; 31 mi) but misidentified it as the French colony of Saint-Domingue on the island of Hispaniola.
[6] The Jamaican Vice-Admiralty court upheld the legality of the British capture of Zong from the Dutch and the syndicate renamed the ship Richard of Jamaica.
[5] When news of the Zong massacre reached Great Britain, the ship's owners claimed compensation from their insurers for the loss of the slaves.
[b] It is possible that the figures concerning the number of people killed, the amount of water that remained on the ship and the distance beyond Jamaica that Zong had mistakenly sailed are inaccurate.
[49] Stubbs was the only witness in the first Zong trial and the jury found in favour of the owners, under an established protocol in maritime insurance that considered slaves as cargo.
The Jury were of opinion there was ...[58][59]Collingwood had died in 1781 and the only witness of the massacre to appear at Westminster Hall was again, Stubbs, although a written affidavit by first mate Kelsall was made available to the lawyers.
[63] The insurers' lawyers replied that Lee's argument could never justify the killing of innocent people; each of the three addressed issues of humanity in the treatment of the slaves and said that the actions of Zong's crew were nothing less than murder.
This led Mansfield to order another trial, because the rainfall meant that the killing of those people, after the water shortage had been eased, could not be justified in terms of the greater necessity of saving the ship and the rest of the slaves aboard.
A summary of the appeal on the Zong case was eventually published in the nominate reports prepared from the contemporaneous manuscript notes of Sylvester Douglas, Baron Glenbervie, and others.
[71][c] Jeremy Krikler has argued that Mansfield wanted to ensure that commercial law remained as helpful to Britain's overseas trade as possible and as a consequence was keen to uphold the principle of "general average", even in relation to the killing of humans.
[73] The revelation that rain had fallen during the period of the killings enabled Mansfield to order a retrial, while leaving the notion of "general average" intact.
He emphasised that the massacre would have been legally justified and the owners' insurance claim would have been valid if the water shortage had not arisen from mistakes made by the captain.
[67] Krikler comments that Mansfield's conclusions ignored the ruling precedent of his predecessor, Sir Matthew Hale, that the killing of innocents in the name of self-preservation was unlawful.
[74] Granville Sharp campaigned to raise awareness of the massacre, writing letters to newspapers, the Lords Commissioners of Admiralty and the Prime Minister (the Duke of Portland).
The London Yearly Meeting of the Society of Friends decided shortly after to begin campaigning against slavery and a petition signed by 273 Quakers was submitted to parliament in July 1783.
[82] The immediate effect of the Zong massacre on public opinion was limited, demonstrating—as the historian of abolitionism Seymour Drescher has noted—the challenge that the early abolitionists faced.
[85][86] The Zong killings offered a powerful example of the horrors of the slave trade, stimulating the development of the abolitionist movement in Britain, which dramatically expanded in size and influence in the late 1780s.
[91][92][93] The 1839 edition of Clarkson's book had an important influence on the artist J. M. W. Turner, who displayed a painting at the Royal Academy summer exhibition in 1840 entitled The Slave Ship.
[100] The historical William Garrow did not take part in the case, and because the Zong's captain died shortly after arriving in Jamaica, his appearance in court for fraud is also fictional.
[103][104] "The Ship They Called The Zong" is a short film that accompanies a 2020 poem of that name by Liam Doyle and features a number of paintings, photographs and wood cuttings representing various aspects of the Transatlantic slave trade.
and also composed of words from the same court report—in a New York Times column op-ed about the Adriana disaster that left hundreds of migrants dead in the Mediterranean Sea.