At the outbreak of the American War of Independence in 1775 Jervis was given the command of ; however, she was surveyed by the dockyard and found unfit for service. He was therefore appointed instead to command of HMS "Foudroyant", the ship he had brought to England as a prize seventeen years earlier. For the first few years of the war, the French supplied arms, funding, and military advice on an informal and limited basis to the newly emerging nation of America. With the signing of the Treaty of Alliance in 1778 and the creation of the Franco-American alliance, the war widened. Jervis spent the first few years of the war patrolling the Channel in "Foudroyant" without seeing any significant action, but as the war reached Europe Jervis was placed under the command of Admiral Augustus Keppel. The Channel fleet, under Keppel, sighted the French fleet intending to enter Brest on 23 July. The British fleet of 30 ships of the line chased the French fleet of 29 ships and engaged them on 27 July in what became known as the First Battle of Ushant. The battle was indecisive and in the political aftermath Jervis provided a stalwart defence of Admiral Keppel at the latter's court-martial, helping to secure Keppel's acquittal.