 In 1805 Conn was given temporary command of the first rate flagship and his old ship "Royal Sovereign" whilst their commanders were on leave; his performance further contributed to his reputation as a reliable and steady officer.On 10 October he returned the "Royal Sovereign" to Admiral Collingwood and took command of the fast new second rate .Eleven days later Conn and his crew were thrown into battle as the Franco-Spanish fleet attempted to break out of Cadiz.