Story: Lighthouses

Page 5. Lights: from oil to electricity

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Innovation

In 1926 New Zealand became the first country in the southern hemisphere to install a radio beacon to assist ships’ navigation. The Marine Department, perhaps to the detriment of maintenance of its existing plant, always sought to improve the lighting and navigational aids associated with lighthouses – foghorns, wireless radios and weather-reporting facilities were installed at some or all of the stations, and upgraded gradually.

Technology

Initially lights were fixed, but because they could be mistaken for shore lights, flashing lights were gradually phased in. Each lighthouse could be identified from out at sea, as every light had a characteristic frequency and duration of flashes, usually, but not always, created by a revolving clockwork mechanism activated by weights.

The lanterns, and the lenses with their clear prisms, were imported. In 1865 James Balfour installed the latest apparatus designed by his Scottish relatives, the Stevensons, to refract and project available light. This innovation was followed by an upgrading of equipment and fuel. In 1876, when the United States was still using lard oil, the New Zealand Marine Department began burning kerosene instead of colza oil (a derivative of the rape plant), and in 1903 it began trialling incandescent acetylene burners, developed only three years before. By 1913 it had installed its first automatic acetylene light in a lighthouse at Bean Rock, Auckland Harbour. The light revolved by the pressure it generated as it burned; an automatic sun valve turned the gas flow on and off.

Bright lights

The electrification of lighthouses saw the use of 1,000-watt bulbs which, when magnified, produced light equivalent to 2.5 million candles.

The end of manned lights

Automated technology at Bean Rock lighthouse raised the possibility of saving money by reducing manual light keeping. In 1915 similar installations at Nelson and Ponui Passage lighthouses saw three jobs go. Cheaper automatic lights, often mounted in previously impossible sites, made it possible to mark new shipping routes.

Between 1921 and 1928, acetylene burners were installed in more towers. In 1935 the lighthouse at Baring Head was the first to prove the efficiencies of electrification. Other stations’ conversion to electric lights after the Second World War meant that oil burners no longer had to be watched, and many more keepers’ positions were lost.

In the 1960s, some lights were permanently de-manned. After a process in 1991 that provoked public concern and keepers’ anger, New Zealand became the first country to totally automate its lighthouses.

Light beacons

In 2005 Maritime New Zealand was maintaining 73 low-range light beacons. The remaining 23 lighthouses, routinely visited and checked every six months, were computer-monitored.

New Zealand had a relatively cheap and effective system of lighting the coasts. Yet the cost of maintaining historic lighthouse towers when virtually maintenance-free and cheap lights can be installed raises questions about their long-term future.

How to cite this page:

Helen Beaglehole, 'Lighthouses - Lights: from oil to electricity', Te Ara - the Encyclopedia of New Zealand, http://www.TeAra.govt.nz/en/lighthouses/page-5 (accessed 23 October 2017)

Story by Helen Beaglehole, published 12 Jun 2006