Cape Willoughby once played a vital role in the shipping trade of the young colony of South Australia before the advent of efficient forms of land transport.
Cape Willoughby Lighthouse was built to assist the safe journey of ships passing through the treacherous stretch of water known as Backstairs Passage during a time of rapidly expanding coastal shipping trade between the eastern colonies and the colony of South Australia.
The lighthouse was originally known as the Sturt Light after the explorer Captain Charles Sturt. The tower took over two years to construct and the workers lived in tents during this time. South Australia's first lighthouse was officially opened in January 1852, and manned 24 hours a day by 3 lightkeepers who lived here with their families.
Cape Willoughby Lighthouse was constructed from locally available granite and lime mortar. Quarrying is evident near the lighthouse atop the cliffs of Devils Kitchen. It is thought holes were hand-drilled into the rock in the quarry and filled with wood. This was kept wet and the expanding wood would crack the rock which was then shaped prior to construction. The result was a circular tower of roughly dressed granite masonry.
The walls of the lighthouse are 1.4m thick at the base and taper to 0.86m thick at the top. The tower, from the base to the balcony, is 20.5 metres high (67 feet and 3 inches) and is round for wind resistance. The interior base of the tower is one of the widest in Australia and the lightkeepers and their families were even known to have hosted parties and dances here.
The original Deville Lantern room housed optical apparatus (light) consisting of 15 multiple wick oil burner lamps. This was reflected intermittently by revolving reflectors powered by a weight driven motor, and appeared as a flashing light. Its greatest intensity was every 1.5 minutes and in clear weather could reach 24 nautical miles.
In 1925 the lantern room and light were replaced by a more modern and powerful Chance Brothers system. The light consisted of a pressurised incandescent kerosene lantern with a three ton revolving Fresnel lens. The lens floated in a bath of mercury to reduce friction when turning. It was driven by 146lb weights which had to be wound up every 2.5 hours working on a system similar in principle as a grandfather clock. The mercury proved to be a health hazard to the lightkeepers.
In 1959 the lighthouse was electrified by two diesel powered generators installed at the station.
The lightstation became fully automated in 1974-75 when 240 volts main power was connected. A standby diesel generator and battery bank provided backup during power failure. The lantern house was also removed and was replaced with new fibreglass lantern housing. The original housing was later installed atop a stub tower in the Kingscote Museum, where it remains to this day.
The original wooden jarrah spiral staircase was also replaced with a steel structure due to wet rot and continual use.
Cape Willoughby Lightstation was one of the last manned lighthouses in Australia. It was officially automated (unmanned) in 1992.
In 2003, the lightstation was downgraded when a ML300 beacon was installed, consisting of a 35 Watt 12 Volt lamp, which is visible for 11 nautical miles. In March 2011, this was replaced with a Vega LED beacon. It is powered by two 12 Volt batteries, and the battery float is charged from the mains.
