Creal Reef Light
Encyclopedia
Creal Reef Light is an active lighthouse
Lighthouse
A lighthouse is a tower, building, or other type of structure designed to emit light from a system of lamps and lenses or, in older times, from a fire, and used as an aid to navigation for maritime pilots at sea or on inland waterways....

 located at Creal Reef, a planar reef about 150 kilometres (93.2 mi) east of Mackay
Mackay, Queensland
Mackay is a city on the eastern coast of Queensland, Australia, about north of Brisbane, on the Pioneer River. Mackay is nicknamed the sugar capital of Australia because its region produces more than a third of Australia's cane sugar....

, Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...

, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

. It guides ships outgoing from Mackay into Hydrographers Passage, a deep water channel east of Mackay. The structure is a stainless steel tower, which also serves as a daymark
Daymark
A daymark or a day marker is a structure such as a tower constructed on land as an aid to navigation by sailors. While similar in concept to a lighthouse, a daymark does not have a light and so is usually only visible during daylight hours...

 and carries a racon
Racon
A racon is a radar transponder commonly used to mark maritime navigational hazards. The word is a portmanteau of RAdar and beaCON.When a racon receives a radar pulse, it responds with a signal on the same frequency which puts an image on the radar display...

.

Creal Reef

Creal Reef is a middle shelf planar reef with an area of 1.6 square kilometre (0.617763453748056 sq mi). It was named in the late 1920s by Captain John A. Edgell (RN
Royal Navy
The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

) on the survey ship HMAS Moresby
HMAS Moresby (1918)
HMAS Moresby was a 24-class "Fleet Sweeping" sloop that served in the Royal Navy and Royal Australian Navy as a minesweeper, anti-submarine vessel, and survey ship...

, during the Moresby survey of the Cumberland Channel inside the Great Barrier Reef
Great Barrier Reef
The Great Barrier Reef is the world'slargest reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2,600 kilometres over an area of approximately...

. It was named after Denis A. J. Creal, a pilot with the No. 101 Flight RAAF
No. 101 Flight RAAF
No. 101 Flight RAAF was a Royal Australian Air Force fleet co-operation flight. The Flight was formed on 1 July 1925 and was equipped with Fairey III amphibian aircraft. These aircraft were replaced with Supermarine Seagull IIIs in 1926. Aircraft from No. 101 flight operated from the Royal...

 who assisted the Moresby with her surveys.

Structure and display

The structure, established in April 1985, is a 21 metres (68.9 ft) stainless steel
Stainless steel
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....

 skeletal tower with a white lantern, standing on a reinforced concrete
Reinforced concrete
Reinforced concrete is concrete in which reinforcement bars , reinforcement grids, plates or fibers have been incorporated to strengthen the concrete in tension. It was invented by French gardener Joseph Monier in 1849 and patented in 1867. The term Ferro Concrete refers only to concrete that is...

 hut, supported on four piles. The total height from the ground to the top platform is 34.5 metres (113.2 ft). The light shares the location with an automatic weather station.

The current light characteristic is a white flash every 7.5 seconds (Fl.W. 7.5s) visible for a distance of 19 nautical miles (35.2 km). The apparatus is a solar power
Solar power
Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar radiation, along with secondary solar-powered resources such as wind and wave power, hydroelectricity and biomass, account for most of the available...

ed VRB-25
VRB-25
The VRB-25 is a lighthouse optical system designed and built by Vega Industries Ltd. in Porirua, New Zealand. It was originally designed in 1993-95 with the assistance of the United States Coast Guard to meet USCG requirements for a robust mechanism requiring minimum maintenance. It has become the...

 rotating at 1.33 rpm. The light source is a 12 Volt
Volt
The volt is the SI derived unit for electric potential, electric potential difference, and electromotive force. The volt is named in honor of the Italian physicist Alessandro Volta , who invented the voltaic pile, possibly the first chemical battery.- Definition :A single volt is defined as the...

 75 Watt
Watt
The watt is a derived unit of power in the International System of Units , named after the Scottish engineer James Watt . The unit, defined as one joule per second, measures the rate of energy conversion.-Definition:...

 Halogen lamp
Halogen lamp
A halogen lamp, also known as a tungsten halogen lamp, is an incandescent lamp with a tungsten filament contained within an inert gas and a small amount of a halogen such as iodine or bromine. The chemical halogen cycle redeposits evaporated tungsten back on to the filament, extending the life of...

 with an intensity of 104,000 cd
Candela
The candela is the SI base unit of luminous intensity; that is, power emitted by a light source in a particular direction, weighted by the luminosity function . A common candle emits light with a luminous intensity of roughly one candela...

. The racon, mounted at an elevation of 34 metres (111.5 ft), transmits a morse code
Morse code
Morse code is a method of transmitting textual information as a series of on-off tones, lights, or clicks that can be directly understood by a skilled listener or observer without special equipment...

 "M" (- -) for a distance of 16 nautical miles (29.6 km).

The daymark, displayed at 33 metres (108.3 ft) above MHWS, comprises two orange 3 by 7 m (9.8 by 23 ) slats on the northern and western faces.

Site operation and visiting

The site and the tower are operated by the Australian Maritime Safety Authority
Australian Maritime Safety Authority
Australian Maritime Safety Authority is responsible, on behalf of the Commonwealth Government of Australia, for the regulation and safety oversight of Australia's shipping fleet and management of Australia's international maritime obligations...

. The island is accessible only by boat, and both the site and the tower are closed to the public.
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