 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 300 yards ( 270 m ) 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 . 
