Corvettes surrender to the Allies that September, the Wehrmacht transferred its Sardinian garrison to Corsica as part of Operation ANTON The Germans arrived before the Allies could get men onto the island, then quickly decided to leave A Free French battalion landed on September 15, in the middle of a hasty German evacuation of only recently disembarked troops As the Germans pulled out, they were harassed by the French, by the Maquis, and even by some Italian troops who switched sides However, the Wehrmacht got most of its men off the island by the first week in October The Western Allies subsequently installed 12th Tactical Air Command on 14 Corsican airfields CORVETTES A series of escort ship types that began with the “Flower” class, which first saw service in July 1940 The top speed of a “Flower” was reduced to just 16 knots by prewar design errors that aimed at enabling it to perform secondary roles in minesweeping and as a fleet tug Flowers proved nearly unseaworthy in bad North Atlantic weather, and at least one broke in half in a storm They were usually built in smaller British yards that could just manage their frames, thereby freeing main yards to build bigger warships Some were built in Canada Longer, faster, twin-screwed “River” class corvettes were built to make up early deficiencies of the “Flowers.” From 1942, “River” ships were reclassified as frigates A third “Castle”-class of corvette was still built for a time in small yards It was longer than a “Flower”-class ship by 35–50 feet and armed with the latest anti-submarine warfare weapons, notably a Squid three-barreled mortar However, frigates proved more capable and stable than any corvette All corvette construction was therefore halted in 1943 to build more “River”-class frigates COSSAC “Chief of Staff to the Supreme Allied Commander.” An AngloAmerican joint planning group established in March 1943 It arose from a decision on invasion planning made at the Casablanca Conference (January 14–24, 1943) It preceded establishment of SHAEF in February 1944 COSSAC set out preliminary plans for the OVERLORD invasion of France and for a supporting series of deception operations that came to be collectively called FORTITUDE The COSSAC plan for the main invasion was approved at the Québec Conference in August 1943, but substantially modified by General Bernard Law Montgomery and others in early 1944 COSSACK POST U.S forces term for a night-time observation post British troops called this a “listening post,” befitting a natural reduction in visual acuity at night COSSACKS Many Cossacks fought against the Germans on the Eastern Front Their horses could maneuver around frozen German guns and vehicles, as during the Moscow offensive operation (December 5, 1941–January 7, 1942) More than 50,000 Cossacks joined an anti-Soviet army set up by the Germans from Soviet prisoners of war and led by ex–Red Army General Andrei Vlasov The Western Allies 270