 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 . 
