 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 . 
