on 27 august, in anticipation of war with nazi germany, the french navy planned to reorganize the mediterranean fleet into the of three squadrons. when france declared war on 3 september, the reorganization was ordered and the 3rd light squadron, which included the 5th and 9th scout divisions with all of the "vauquelin"-class ships, was assigned to the 3rd squadron. the squadron transferred to oran, french algeria, on 3 september and the ships of the 9th scout division were assigned to escort duties in the western mediterranean in early october. on 22 december "kersaint", "maillé brézé" and the large destroyers , and rendezvoused with force z, the battleship and the light cruisers and , which was escorting four cargo ships loaded with american aircraft to casablanca, french morocco. a few days before the french surrender on 22 june, "kersaint" escorted the seaplane carrier from toulon to oran, despite being only able to steam on one propeller shaft, and then proceeded to nearby mers-el-kébir. the ship was present when the british attacked the fleet in the port on 3 july lest the ships be turned over to the germans, but managed to escape to toulon without damage, even though her maximum speed on one shaft was only .