Both public and official opinion had been shocked when news of the horrors of the Second Fleet reached England.
An inquiry had been held but no attempt had been made to arrest Donald Traill, master of Neptune and described as a demented sadist, or bring a public prosecution against him, the other masters, or the firm of contractors.
They had already been contracted by the government to prepare the Third Fleet for sailing to Port Jackson in 1791.
Traill and his Chief Mate William Ellerington had been privately prosecuted for the murder of an unnamed convict, seaman Andrew Anderson and John Joseph, cook, but after a trial lasting three hours before Sir James Marriott in the Admiralty Court, the jury had acquitted both men on all charges "without troubling the Judge to sum up the evidence".
The Third Fleet comprises eleven ships that had set sail from the United Kingdom in February, March and April 1791, bound for the Sydney penal settlement, with more than two thousand convicts aboard.
The passengers comprise convicts, military personnel and notable people sent to fill high positions in the colony.
More important for the fledgling colony is that the ships also carry provisions.
The first ship to arrive in Sydney is the Mary Ann with its cargo of female convicts and provisions on July 9, 1791.
The Mary Ann can only state that more ships are expected to be sent.
The Mary Ann had sailed on her own to Sydney Cove, and there is some argument about whether she was the last ship of the Second Fleet, or the first ship of the Third Fleet.
The ships that make up each fleet, however, are decided from the viewpoint of the settlers in Sydney Cove.
For them, the second set of ships had arrived in 1790 (June), and the third set of ships arrives in 1791 (July–October).
The Mary Ann is a 1791 arrival.
The next ship to arrive, just over three weeks later, on August 1, 1791, is the Matilda, which bringss news that there are another nine ships making their way for Sydney, and which are expected to arrive shortly.
The final vessel, the Admiral Barrington, does not arrive until October 16, nearly eleven weeks after the Matilda, and fourteen weeks after the Mary Ann.
One hundred and seventy-three male convicts and nine female convicts had died during this voyage.
This death rate is high but nowhere near as bad as what had occurred on the Second Fleet.
The first free settlers arrive in 1791.