The Germans had around 5,000 troops in the immediate area of St Nazaire. The port was defended by the 280th Naval Artillery Battalion under the command of "Kapitän zur See" Edo Dieckmann. The battalion was composed of 28 guns of various calibres from 75 mm to 280 mm railway guns, all positioned to guard the coastal approaches. The heavy guns were supplemented by the guns and searchlights of the 22nd Naval Flak Brigade under the command of "Kapitän zur See" Karl-Konrad Mecke.