Dent Island Light

Dent Island Light is an active lighthouse located on Dent Island, a small island off the coast of Queensland, Australia. Dent Island is part of the Whitsunday Group of the Whitsunday Islands. Located on the south-west tip of the island, the light guides ships passing in the Whitsunday Passage, between Whitsunday Island and the islands to the west,[2] and marks the Dent Island Passage.[3]

Dent Island Light
Dent Island Lightstation, 2007
Queensland
LocationDent Island
Queensland
Australia
Coordinates20°22′09.31″S 148°55′44.17″E
Year first constructed1879
Automated1987
Constructiontimber frame clad with galvanized iron
Tower shapeconical tower with balcony and lantern
Markings / patternwhite tower and lantern, red lantern dome
Tower height33 feet (10 m)
Focal height121 feet (37 m)[1]
Original lens4th order
Current lensML-300
Light sourcesolar power
Intensity1785 cd
Range10 nautical miles (19 km; 12 mi)
CharacteristicFl.W. 5s
Admiralty numberK3064
NGA number111-10204
ARLHS numberAUS-188
Managing agentAustralian Maritime Safety Authority
Heritagelisted on the Commonwealth Heritage List 

From its inception, the lighthouse was closely connected to Cape Cleveland Light. Both lighthouses were recommended, approved, tendered and finally, in December 1879, constructed together. The light went through two upgrades in the 1920s replacing both the oil lamp and the fourth order lens with an incandescent gas mantle and a new lens. In 1983, the light was converted to solar power, and finally, in 1987 it was demanned.[2]

The lighthouse is a typical for Queensland, made of a timber frame clad with galvanized iron plates. It is topped by a Chance Brothers lantern room, and painted white with a red dome.[2] A modern ML-300 lantern replaced the original lens.[4]

History
A 1917 photo of the lighthouse

From its beginning, the lighthouse was closely related to the Cape Cleveland Light. The construction of both lighthouses was recommended by Commander George Poynter Heath, the Chairman of the Queensland Marine Board, in February 1878.[2] The lighthouses were formally approved in April 1878 and tenders for the construction of both stations, each including a lighthouse and two keepers' cottages, were called in May 1878 and closed in June 1878.[5] The tenders were awarded to W. P. Clark, who also constructed Bustard Head Light (1868),[6] Low Isles Light (1877),[7] Double Island Point Light (1884) and Pine Islet Light (1885).[6] However, following personal difficulties,[6] the contracts were transferred to John Clark and James Wiseman who completed the construction of both stations in December 1879.[5]

The tower was constructed in the unique Queensland method of constructing a timber frame and cladding it with non-structural iron plates or iron sheets.[2] The original apparatus comprised a fourth order lens with an oil wick burner[8] of 4,000 cd intensity.[2] Like other lighthouses at that time it used a clockwork mechanism with weights, which had to be wound periodically. Due to its short height, only 6 metres (20 ft) from the base to the lantern,[4] the mechanism had to be wound every 75 minutes.[9]

In 1925,[10] the light was upgraded to a 35mm incandescent gas mantle fueled by pressurised kerosene, with an intensity of 225,000 cd,[11] visible for 18 nautical miles (33 km; 21 mi).[2] In 1927 the lens was replaced with refurbished lens from Cape Cleveland Light.[2]

In 1983[12] the light was converted to solar power and downgraded to a visibility range of 10 nautical miles (19 km; 12 mi).[2] It was finally demanned in 1987.[4]

Current display

The current light characteristic is a white flash every five seconds (Fl.W. 5s) visible at 335°-167°, for a distance of 10 nautical miles (19 km; 12 mi).[13] The apparatus is an ML-300 and the light source is a 12 Volt 35 Watt Halogen lamp with an intensity of 1785 cd.[4]

Plans for the tower, 1878

Structures

The tower is 6 metres (20 ft) from the base to the lantern,[4] conical in shape. It is built of an internal timber frame, clad with galvanized iron plates, painted white.[2] Access from the entrance to the lantern is via a circular cast iron staircase.[2] The tower is topped by a 6 feet 7.75 inches (2.0257 m) diameter Chance Brothers lantern room, white painted with the dome painted red.[2] The modern ML-300 lens is installed inside the lantern room.[14]

The station includes two cottages, constructed in 1960, timber-framed, fibro clad, with galvanised iron roofs. One of the cottages has two storeys and a closed verandah, while the other is single levelled with an open verandah. The station also comprises a winch house, stores shed, engine room and combined workshop/radio room.[2]

Site operation and visiting

The light is operated by the Australian Maritime Safety Authority. The island is accessible only by boat. However, Dent island is privately owned, so the site is closed to the public.[3]

See also

Notes
  1. List of Lights and AN362-01. Rowlett lists "37 m (127 ft)" which seems like a unit conversion error.
  2. AHD105369.
  3. Rowlett.
  4. AN362-01.
  5. QLD601794.
  6. AHD100383.
  7. Low Isles Light.
  8. AHD105369. Lighthouses of Australia Inc says it was a kerosene burner.
  9. Lighthouses of Australia Inc.
  10. AHD105369. Lighthouses of Australia Inc says 1926-1927.
  11. AHD105369. Lighthouses of Australia Inc says 50,000 cd.
  12. AN362-01. Lighthouses of Australia Inc says 1981. AHD105369 states a conversion to electricity in 1982.
  13. List of Lights
  14. AN362-01. AHD105369 says the lens installed on the handrail of the tower balcony, but recent photos show it inside the lantern room.

References
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