Battle of the Îles Saint - Marcouf The Battle of the Îles Saint - Marcouf was an engagement fought off the Îles Saint - Marcouf near the Cotentin peninsula on the Normandy coast of France in May 1798 during the French Revolutionary Wars . In 1795 a British garrison was placed on the islands , which operated as a resupply base for Royal Navy ships cruising off the coast of Northern France . Seeking to eliminate the British presence on the islands and simultaneously test the equipment and tactics then being developed in France for a projected invasion of Britain , the French launched a massed amphibious assault on the southern island using over 50 landing ships and thousands of troops on 7 May 1798 . Although significant Royal Navy forces were in the area , a combination of wind and tide prevented them from intervening and the island ' s 500 - strong garrison was left to resist the attack alone . Despite the overwhelming French majority in numbers , the attack was a disaster : nearly 1 , 000 French soldiers were killed as the boats were caught in open water under the island ' s gun batteries : several were sunk with all hands . Heavy fire from batteries and Royal Marines prevented a single French soldier from landing and the retreating fleet was subject to heavy fire from the smaller island to the north , inflicting further losses . British casualties were negligible . Although this operation indicated the probable result of a full - scale invasion of Britain , the threat remained and British forces began a close blockade of the surviving landing craft that were anchored in the Cotentin ports . A month after the battle this strategy resulted in a secondary success when a French frigate and corvette passing along the coast were intercepted and defeated by the blockade squadron . Background . Throughout the French Revolutionary Wars , British warships patrolled the French coast , intercepting and destroying French maritime traffic and blockading French ports . In 1795 Captain Sir Sidney Smith , a prominent Royal Navy officer , recognised that if resupply points could be established on islands off the French coast then cruising warships could extend their time at sea . To this purpose , Smith seized the uninhabited Îles Saint - Marcouf , which lie off Ravenoville on the Cotentin peninsula in Normandy . Smith constructed barracks and gun batteries and manned the islands with 500 sailors and Royal Marines , including a large proportion of men unfit for ship - board service , described as " invalids " . The islands were regularly supplied with food from the British mainland , and bags of earth brought by visiting vessels allowed the development of a vegetable garden . Smith supported the islands with several gunvessels , including the converted hoys , , and , and the " Musquito " - class floating battery , which he had had purpose - built for the defence of the islands . Lieutenant Charles Papps Price , captain of " Badger " and an unpopular officer who had repeatedly been passed over for promotion , commanded the British occupation ; Price spent most of his time on the islands with a prostitute he had brought from Portsmouth . Since the 1796 French victory in Italy over the Austrians , pressure had been growing in France for direct action against Britain . Command of an army deployed in Northern France and named the " Armée d ' Angleterre " was initially given to General Napoleon Bonaparte , but later passed to General Kilmaine . Bonaparte , and then Kilmaine , prepared for an invasion of Britain and Captain Muskein , a naval administrator from Antwerp , was instructed to develop a suitable fleet of landing craft to convoy the troops across the English Channel . The French Directory commissioned a Swedish naval architect Fredrik Henrik af Chapman to design the invasion barges and by 1797 ships of his design were under construction along the Northern French coast under Muskein ' s supervision : the boats were known to the French soldiers as " " bateaux à la Muskein " " ( Muskein - type boats ) . In April 1798 , Muskein was ordered to prepare a squadron of his barges for an attack on the Saint Marcouf Islands . The operation was intended simultaneously to eradicate the British garrison and restore French control of the raiding base , test the effectiveness of the barges in a military amphibious operation , and focus British naval attention on the English Channel and away from Bonaparte ' s preparations at Toulon for the invasion of Egypt . On 7 April 1978 , Muskein sailed from Le Havre with 33 barges under the command of General Point , but on 8 April he found his passage blocked by the British frigates HMS " Diamond " under Captain Sir Richard Strachan and HMS " Hydra " under Captain Sir Francis Laforey . At 16 : 00 the frigates cornered the barges in the mouth of the River Orne and opened fire , but " Diamond " grounded soon afterwards and although the frigate was brought off after darkness , neither side was able to inflict serious damage . On 9 April the French flotilla was able to leave the Orne River and anchor in the harbour of Bernières - sur - Mer , but the arrival of the fourth rate HMS " Adamant " under Captain William Hotham persuaded Muskein to return to the more sheltered anchorage at the mouth of the Orne . As he returned eastward , he again came under fire from " Diamond " and " Hydra " . The French flotilla then sheltered under the batteries at Sallenelles until the damage was repaired . Over the next two weeks , however , the situation changed – Rear - Admiral Jean Lacrosse at Cherbourg had been informed of Muskein ' s difficulties and sent reinforcements of 40 barges and armed fishing ships to Sallenelles . Late in April , Muskein had an opportunity to escape without interception by the British force offshore and sailed as far as Saint - Vaast - la - Hougue , to the west of the islands . There he waited for the right combination of wind and tide to allow the attack to go ahead uninterrupted by the British squadron that had followed his flotilla westwards . Battle . On 6 May the conditions for Muskein ' s attack were perfect : the calm winds prevented the British warships intercepting his flotilla , and the weak tides prevented disruption to his craft by heavy waves . The British also were aware of the conditions necessary for the attack , and made swift preparations to arm the batteries and line the shore with Royal Marines . A small boat from the islands watched as Muskein ' s force rowed out of Saint - Vaast - la - Hougue and steadily approached the islands during the evening . The sixth rate HMS " Eurydice " under Captain John Talbot and the brig HMS " Orestes " under Commander William Haggitt , had joined " Adamant " , which was stranded away from the islands by the calm . Despite strenuous efforts , the three vessels would not be able to reach the islands in time to take part in the action . At midnight , the island ' s boat signaled the approach of the French and Lieutenant Price readied the defences . Muskein ' s force mustered 52 vessels , including a number of brigs that mounted several large cannon and were intended to provide covering fire for the landing barges . The main body of the attacking troops numbered between 5 , 000 and 6 , 000 French soldiers drawn largely from coastal defence units based around Boulogne . Unwilling to risk a night attack , Muskein waited until dawn , using the remaining cover of night to draw his craft in formation facing the western defences of the southern island . The gunbrigs lay offshore , behind the landing barges whose approach they would cover during the attack . As dawn broke , Muskein ordered the advance and the gunbrigs and smaller cannon in the barges opened fire on the British defences . The West Island ' s batteries , under Lieutenant Price , consisted of 17 cannon : four 4 , two 6 , and six 24 - pounder long guns , and three 24 , and two 32 - pounder carronades . Although eight of the guns were relatively light , the batteries inflicted devastating damage on the light invasion craft . Despite severe casualties the French barges continued their approach until they were within musket range , . The garrison of Royal Marines opened fire and the artillery crews switched to canister shot . Six or seven boats sank with their entire crews and troops , and others were heavily damaged . Losses were so high that the French called off the attack ; even so , the return journey carried the barges past East Island , which was under the command of Lieutenant Richard Bourne of " Sandfly " and mounted a battery of two 68 pounder carronades , massive guns that inflicted additional severe losses . Although Hotham ' s squadron made desperate efforts to reach the battle , the wind was too light and they were only able to chase the remaining ships back into Saint - Vaast - la - Hougue . Aftermath . The battle was a disaster for the French . According to unofficial accounts , they lost approximately 900 men killed or drowned and at least 300 wounded , in addition to the loss of a number of the newly - constructed landing craft . In France the newly appointed Minister of Marine Étienne Eustache Bruix ordered a second attempt on the islands soon afterwards but the orders were immediately countermanded by the French Directory , which did not want the embarrassment of a second disastrous attack . Instead , Lacrosse gave orders for most of the surviving ships to be sent to Cherbourg , detachments later reaching Saint Malo and Granville . Muskein was ordered to return to Le Havre with the remainder . In Britain the successful defence of the islands was highly praised and Price was promoted as a reward , although Bourne was not , despite a recommendation in the official report . British losses included a single marine killed and four other personnel wounded . The victory was seen in Britain as a foreshadowing of the likely fate of an attempted invasion and helped ease British fears about the threat of a French amphibious attack . Nearly five decades later the Admiralty issued the Naval General Service Medal with clasp " Isles St . Marcou " upon application to all British participants then still living . The British strengthened the islands ' defences , in case of further attacks , and a number of warships patrolled the area to observe French movements and intercept any flotillas of invasion craft . At the Action of 30 May 1798 , this strategy achieved an unexpected success when HMS " Hydra " intercepted the French frigate " Confiante " and a corvette off the mouth of the River Dives . The British drove " Confiante " ashore and boarding parties later burnt her . The islands remained under British occupation without any further French attacks until 1802 . The Peace of Amiens returned the islands to French control ; throughout the Napoleonic Wars of 1803 – 1815 they remained French , protected by a significant garrison .