HMS "Shannon" had been off Boston for 56 days and was running short of provisions, whilst the extended period at sea was wearing the ship down. She would be at a disadvantage facing USS "Chesapeake", fresh from harbour and a refit. A boat was despatched carrying the invitation, manned by a Mr Slocum, a discharged American prisoner. The boat had not reached the shore when "Chesapeake" was seen underway, sailing out of the harbour. She was flying three American ensigns and a large white flag at the foremast inscribed 'Free Trade and Sailor's Rights'. "Shannon" carried 276 officers, seamen and marines of her proper complement, eight recaptured seamen, 22 Irish labourers who had been 48 hours in the ship, of whom only four could speak English, and 24 boys, of whom about 13 were under 12 years of age. Broke had trained his gun crews to fire accurate broadsides into the hulls of enemy vessels, with the aim of killing their gun crews, rather than attempting to disable the enemy ship by firing at the masts and rigging. This was, however, the standard Royal Navy practice of the time, only Broke's efficiency in gunnery training distinguished him in this regard. Lawrence, meanwhile, was confident in his ship, especially since she carried a substantially larger crew. Previous American victories over Royal Navy ships left him expectant of success. Just before the engagement, the American crew gave three cheers.