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Tasman lighthouse lens and pedestal

Manufacturer Chance Bros & Co Ltd

Date1905

Object number00015662

NameLighthouse lens

MediumCast iron, flint glass

DimensionsOverall: 6000 mm

ClassificationsVisual communication

Credit LineANMM Collection Transfer from Australian Maritime Safety Authority

Terms

DescriptionLighthouse lens and pedestal constructed in 1906 for a light station on Tasman Island, in Storm Bay off Cape Pillar, in south-east Tasmania . HistoryIn the early years of the Australian colonies there were few lighthouse structures. Tasmania was the site of the second lighthouse built, on Iron Pot Inlet in 1832 at the mouth of the Derwent River. During the mid-19th century, trade and settlement brought more and more people to the colony, and much more shipping activity. Tragic shipwrecks in the Bass Strait around King Island north west of Tasmania resulted in the construction of a number of lights by the end of the 19th century. Several were built around Tasmania including the lighthouse on Tasman Island, in Storm Bay off Cape Pillar, south east of Tasmania in 1906. The Tasman lighthouse and the first-order dioptric lens were shipped out from England where they had been manufactured by the famous lens makers the Chance Bros. This company had begun production of glass prisms for lighthouses in the mid-nineteenth century and had perfected both the brass frames to hold the glass and clockwork motors to turn the lens. The lens was constructed according to the design of Augustin-Jean Fresnel. It is made up of five panels each comprised of 127 pieces of flint glass in a brass frame (the astragal bars). The flint glass sections are arranged in a succession of concentric rings which ultimately form the centre bullseye. The lens sits on a cast iron table which in turn sits on the pedestal. The light from this lens flashed every five seconds and was said to be visible for more than 30 nautical miles (55 km). It is a first-order refractive lens - the most powerful type. Because of the location of the lighthouse high on cliffs, the five panels of the lens had to be tilted. The lens, its heavy pedestal and steel tower all had to be hauled up onto the rugged 250 meter-high Tasman island. It is impossible to land directly on the island and everything, including people and livestock had to be landed on an adjacent rock and swung across to the island on a flying fox. Everything was then pulled up the cliffs - at first by a horse-drawn tramway, which was later mechanised. Contact between the mainland and the lighthouse keepers on Tasman Island was often by carrier pigeon until wireless communication was established in 1930s. There was little wildlife other than mutton birds and feral cats and early cutting of timber for fuel left the island without trees. Work was often dangerous for those maintaining facilities on the island and in 1927 while working on the crane one person died. In 1977 the Tasman Island lighthouse was fully automated and the lens removed. The light today consists of a series of sealed beams that are operated by a battery charged by a wound generator. The lens and pedestal are six meters high. Today, an electrical source turns the light, but the original clockwork motor made by Chance Bros of Birmingham can still be seen. SignificanceThe Tasman lighthouse lens and pedestal are a reminder of the past and continuing role of lighthouses in contributing to the safety of shipping in Australian waters. The Tasman Island lighthouse is one of Australia's most isolated and tallest lighthouses, and highlights the hardships experienced by early lighthouse keepers.