Born in 1766 in Algiers, where his father was Consul general, Bayntun joined the navy at a young age and received his lieutenancy at just seventeen on 15 April 1783. When war broke out with Revolutionary France in 1793, Bayntun was sent to the West Indies under Admiral Sir John Jervis and, after taking part in the capture of Martinique, he was given command of the sloop. Bayntun was also present during the invasion of Guadeloupe and on the 4 May 1794, he was appointed post captain of HMS Undaunted, the former French frigate, La Bienvenue, captured during the Battle of Martinique. Bayntun was subsequently given command of the 36-gun HMS Reunion, which was wrecked in December 1796. In January 1799, he was appointed to. He then commanded ships of the line, including and, with which he won acclaim during a successful blockade of the French Caribbean islands following their return to France under the terms of the Treaty of Amiens. In 1803 he captured the French frigate Créole, along with her convoy and hundreds of troops aboard returning to France.
Trafalgar campaign
In 1804 Bayntun returned to England after ten years in the West Indies, and was given command of the fast third rate. She joined Nelson's fleet off Brest and subsequently sailed to the West Indies again in pursuit of the French fleet. After learning that the French had returned to European waters, Leviathan sailed to Gibraltar before arriving off Cadiz on 8 October 1805. Bayntun was in this way unusual amongst Trafalgar captains, many of whom had only just arrived on station for the blockade. At the Battle of Trafalgar on 21 October, Bayntun in Leviathan was fifth in Nelson's weather column, after,, and HMS Conqueror. Leviathan raked the French flagship before engaging the massive. Seeing the distant approach of Rear-Admiral Dumanoir's squadron from the north, Captain Thomas Hardy ordered Leviathan and other ships to close with the enemy. Leviathan engaged the Spanish ship, which was supported by Intrepide. Conqueror then joined the fight and Bayntun was able to lay his ship alongside the badly damaged San Augustin whilst continuing to fire into Intrepide. As the 74-gun HMS Orion passed, Bayntun shouted at her captain, Edward Codrington, "I hope you will make a better fist of it!" Some time later, with 160 of his crew dead or wounded, Commodore Don Fellipe of the San Augustin surrendered his sword to Bayntun. Of Leviathan's crew, four had been killed and just over 20 wounded during the battle. After the battle, with the weather worsening and concerns of a counter-attack; Vice-Admiral Collingwood, in command since the death of Nelson, ordered many of the prizes destroyed. Bayntun co-ordinated the evacuation of the ships closest to him which were to be scuttled. Bayntun's report on the matter stated that; although he had done his best to carry out the orders he'd been given, due to the weather, "...much less has been done than I most ardently wished and many boats have been lost." Leviathan also lost her prize, the San Augustin, which was burnt as she foundered some days after the action. The Leviathan suffered little damage during the battle and subsequent storm, and was able to return to Gibraltar unaided. Bayntun was the guidon bearer at Nelson's state funeral during the water procession between Greenwich and Whitehall. He was also among the many officers that the Lloyd's Patriotic Fund honoured with gifts.
