Cocos shows the power of communications

Only twelve days separated Emden's success at Penang from the end of her raiding career at Cocos. While attacking the communications station, Emden allowed a signal to reach a convoy and underestimated how quickly Sydney could arrive. Emden opened fire first at about six nautical miles, but Sydney's heavier six-inch guns disabled the German cruiser's funnels, wireless, steering, and engines before Emden beached herself. The action became the Royal Australian Navy's first fight under its own flag. Claims that Sydney fired only four salvos conflict with reports of roughly 670 rounds, so the sources may mean four groups of rapid fire instead of four individual broadsides. Once Emden's position was reported, her operational freedom collapsed. The conflicting numbers also show why battle accounts need internal checking.