Battle of Cartagena ( 1758 ) The Battle of Cartagena took place on 28 February 1758 off the Spanish port of Cartagena during the Seven Years War . A British fleet under Henry Osborn , which had blockaded a French fleet in Cartagena , attacked and defeated a French force under Michel - Ange Duquesne de Menneville coming to their assistance . The interception of the French fleet ensured that only limited assistance would come to the French fortress of Louisbourg in North America , which was besieged by British forces and fell later that year . Background . In 1756 a French expedition sailed out of Toulon and captured Minorca . After this French ships withdrew to Toulon and did not attempt to depart for the next eighteen months . Operating from their base at Gibraltar British ships mounted an effective blockade at the mouth of the Mediterranean . In 1757 a British attempt to capture Louisbourg in North America had been frustrated by a build - up of French ships in the surrounding area . The French hoped to adopt a similar strategy for 1758 , and decided to send the Brest fleet to boost their forces around Louisbourg . In November 1757 a French force of fifteen ships under Admiral La Clue sailed from Toulon , but following a storm on 30 November they were forced to take shelter in the port of Cartagena , in neutral Spain . They remained there as the British under Henry Osborn moved to bottle up the French in port . Osborn had orders to prevent the French from escaping from the Mediterranean . He received word that a French reinforcement of three ships - of - the - line had set sail from Toulon under Michel - Ange Duquesne de Menneville , intending to combine with La Clue . Two other ships , after failing to capture a British convoy , had also managed to slip into Cartagena to reinforce La Clue . Battle . Osborn was cruising off Cartagena when he sighted Duquesne ' s ships approaching . Spotting the larger British force , Duquesne ordered his ships to scatter . With the bulk of his force , Osborn made sure that La Clue was still trapped in Cartagena so he could not come out to help Duquesne . He detached ships to pursue the retreating French . The " Orphee " was caught and overpowered by three British ships while the " Oriflamme " was deliberately run aground to save it from capture . The third ship " Foudroyant " , Duquesne ' s flagship , tried to outrun the danger but was pursued by the " Monmouth " . After a chase that lasted into the night , the " Monmouth " caught up with the French ship and began to engage it . " Monmouth " s captain , Arthur Gardiner , was killed in the fighting . Ultimately the " Foudroyant " surrendered and Duquesne was taken as a prisoner , ending the battle . Aftermath . By July Osborn decided it was too late in the year for the French to sail to North America , and he withdrew from around Cartagena to allow his ships to re - supply . Also coming to the conclusion that there was nothing he could do to assist Louisbourg , which fell on 26 July , La Clue and his ships sailed back to Toulon rather than attempt to force their passage through the Straits of Gibraltar . The battle went a long way to restoring the reputation of the Royal Navy which had been badly tarnished in the wake of the Fall of Minorca in 1756 , which ultimately resulted in the execution of Admiral John Byng for " failing to do his utmost " to save Minorca . This was particularly the case as Arthur Gardiner had Byng ' s flagship at the Battle of Minorca and his death while fighting served to remove the allegation of cowardice against him . The campaign offered an example of the " tight blockade " tactics that the British would use even more vigorously the following year , made possible by an innovation in naval warfare because of developments in supplying ships at sea .