The King William was fitted at Deptford in spring 1840 for the conveyance of 180 convicts from Ireland to Sydney.
The Guard commanded by Lieutenant Montgomery of the 80th regiment were embarked on 30th March while the ship still lay at Deptford. The Guard consisted of Ensign John Guise Rogers Aplin, of the 28th regiment and 29 rank and file of the 80th and 96th regiments with four women and seven children and two soldier boys.
Surgeon Campbell France
Campbell France also joined the vessel at Deptford. He kept a Medical Journal from 30 March to 24 August 1840. He rejected two of the soldiers who were unwell and they were sent back on shore. 
On the 1st April the ship sailed for Dublin where 180 convicts were embarked at Kingstown Harbour.
According to the surgeon most of the prisoners from the country towns were healthy young men, but those from Dublin city had lately suffered from sickness and the constitutions of many others were impaired. 
Nine free passengers, the sons of convicts were also embarked at Kingstown Harbour including -
Patrick Moran, son of Michael Moran;
Michael, John and Thomas Ryan, sons of Patrick Ryan;
John Ryan son of Richard Ryan;
John and Patrick Hughes sons of Edward Hughes.
The King William departed Kingstown on the 28th April 1840.
Although the weather was fine and mild in the early part of the voyage, many suffered with sea sickness. On 17th May the ship entered the tropics and there was some illness due to the heat at this time. They crossed the equator on 4th June and on the 16th passed the tropic of Capricorn.
On entering the southern hemisphere the weather became cold and stormy. The ship being small with open bulwarks, the decks were always wet in stormy weather and the Hospital and prison were repeatedly flooded by the sea pouring down the hatchways. Many of the guard and convicts suffered from catarrhal, rheumatism and diarrhoea at this time. 
The King William arrived in Port Jackson on the 17 August 1840.
Notes and Links
1). Campbell France was employed on the convict ships Asia in 1828 (VDL) York in 1831, John Barry in 1839 and the King William in 1840.
 Journal of Campbell France. Ancestry.com. UK, Royal Navy Medical Journals, 1817-1857 Original data: Medical Journals (ADM 101, 804 bundles and volumes). The National Archives. Kew, Richmond, Surrey.