Evan Evans was included in the Navy List of Medical Officers in 1814 
Evan Evans was employed as Surgeon Superintendent on the convict ships Malabar in 1819 and the Phoenix in 1822.
He kept unusually detailed journals throughout both voyages.
The prisoners of the Malabar were landed on Friday 5th November and surgeon
Evan Evans described the landing of prisoners of the Malabar in his Journal -
'At 5am 5th November 1819 the convicts were all landed with their rations.
At 10am His Excellency the Governor inspected the convicts in the jail yard and asked them if they had any complaints to make and if they were perfectly satisfied with their treatment during the voyage when they all answered that they had no complaint to make, and were perfectly satisfied with their treatment. And His Excellency was pleased to express his entire satisfaction at their appearance and very healthy state. In closing the foregoing journal I have great satisfaction in stating that the 170 convicts, 32 soldiers comprising the guard, 9 women and 6 children embarked in England in the Malabar were all landed at Sydney in perfect health not a single person lost during the voyage; they were at all times very healthy.
The convicts were allowed to be on deck as much as possible consistent with the safety of the ship. The greatest attention was at all times paid to ventilation and cleanliness. The excellent quality of the provisions, the commodious way these ships are fitted out and the liberal supplies of every comfort in case of sickness, for the convicts, all tend no doubt to preserve them in that good state of health which was the case throughout the voyage in the Malabar. The convicts with very few exceptions on board the Malabar behaved quiet and orderly and their treatment was at all times humane and lenient.' 
Evan Evans described preparation and departure from England in his Journal -
19 October 1821: Joined the ship at Deptford and reported to Captain Young, agent for transports.
27 October 1821: A detachment of the 3rd Regiment embarked on board as Guard over convicts.
4 November 1821: The ship dropped down from Deptford and arrived at Portsmouth on the 8th.
10 November 1821 at Portsmouth: Embarked 120 convicts from the Leviathan Hulk, and 64 from the York.
11 November 1821 at Spithead: Issued the bibles, testaments, prayer books etc to them [convicts] before the divine service.
30 November 1821 at Spithead: In consequence of the severity of the gale last night, the ship drove some distance, and this day the crew were employed in getting the anchors up and in working the ship to an anchorage at the Motherbank which took up most of the day, consequently very few convicts permitted on deck
20 December 1821 at Motherbank: 9am the ship getting under weigh. The convicts with colds are nearly well today. The vaccination not having the least effect. 2pm working out of St Helens.
21 December 1821 in the Channel: 9am blowing very hard and has blown a hard gale all night, mostly from the SW. The prison very wet, leaking in every direction over the prison and most of the convicts very sea sick, bearing up for Dungeness. At 10am had the convicts with their wet things on deck, fire in the airing stove in prison, and had the prison well dried. 
The Morning Post announced in April 1823 that Evan Evans had been appointed surgeon on the Ocean convict ship to New South Wales. . This did not eventuate however as it was announced that Evan Evans had retired because of ill health. 
James McTernan joined the Ocean as Surgeon just one day before she sailed.
 Navy List
 The Royal Navy. The Morning Post (London, England), Monday, April 07, 1823; Issue 16243. British Library Newspapers, Part II: 1800-1900.
 Portsmouth, Portsea, Gosport . The Hampshire Chronicle, etc (Hampshire, England), Monday, April 28, 1823; pg. 4; Issue 2614. British Library Newspapers, Part V: 1746-1950.
 Journal of Evan Evans on the voyage of the Malabar in 1819. Ancestry.com. UK, Royal Navy Medical Journals, 1817-1857 . The National Archives. Kew, Richmond, Surrey.
 Journal of Evan Evans on the voyage of the Phoenix in 1822. Ancestry.com. UK, Royal Navy Medical Journals, 1817-1857 . The National Archives. Kew, Richmond, Surrey.