In Newcastle, NSW, Australia, in the early days of the settlement, one of the most pressing problems was to make the port safe for shipping. One attempt to provide navigational aids was the building (in about 1865) of twin towers in which fires were lit at night. Once these were aligned, theoretically a helmsman had dead reckoning for the harbour channel. But as they were only 68.5 metres apart, in rough seas on a plunging deck, the navigator had major problems in holding his course for the lights. Only one of these beacons now remains and it can be seen at the top of Tyrrell Street.   

Read more at http://www.abc.net.au/local/stories/2012/03/27/3464691.htm