 Great Britain and France had been at war for more than two years by April 1795 , and British dominance at sea was well established , with the Royal Navy maintaining substantial blockade fleets off all of the principal French naval ports . The biggest port on the French Atlantic coast was at Brest in Brittany , from which French raiders could attack British shipping in the English Channel and Western Atlantic . The most efficient commerce raiders were frigates , light and fast warships that could strike rapidly and with devastating effect if left unopposed . One of the major roles of the British blockade squadrons was the detection and elimination of French frigates as they emerged from their bases . 
