Hydrographic Survey Bench Mark, East Trinity facts for kids
Quick facts for kids Hydrographic Survey Bench Mark |
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Hydrographic Survey Bench Mark, East Trinity, 2013 (note mobile phone at base of rock for scale
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| Location | Bessie Point, off Pine Creek-Yarrabah Road, East Trinity, Queensland, Australia |
| Design period | 1870s - 1890s (late 19th century) |
| Built | 1878 |
| Architect | Royal Navy |
| Official name: Hydrographic Survey Bench Mark, 1878, Bessie Point | |
| Type | state heritage (built) |
| Designated | 9 May 2014 |
| Reference no. | 602833 |
| Significant period | 1870s |
| Builders | Royal Navy |
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The Hydrographic Survey Bench Mark is a special marker found at Bessie Point, near East Trinity, Queensland, Australia. It was created by the Royal Navy in 1878. This marker is also known as Bessie Point. It was added to the Queensland Heritage Register on May 9, 2014, because of its historical importance.
Contents
What is a Bench Mark?
A bench mark is a special mark carved into a large rock. This one is on the west side of Bessie Point, in Trinity Bay. It was carved in February 1878 by Lieutenant Edward Richard Connor of the Royal Navy.
This mark helped sailors know the depth of the water in Cairns Harbour. It showed the "datum," which is a reference point for low tide. This bench mark is important because it shows how people surveyed the Queensland coast in the 1800s. It also shows how Cairns grew into an important port.
Why Was Cairns Important?
The Gold Rush and New Ports
In 1876, gold was found at the Hodgkinson goldfield. Trinity Bay was chosen as the closest port for this gold. Before this, Cooktown was the main port for gold, but it was too far north.
The first settlers arrived in Trinity Bay in October 1876. Cairns officially became a port on November 1, 1876. A nearby town called Smithfield was also planned, but it was mostly abandoned after floods in 1877.
Cairns vs. Port Douglas
In 1877, Port Douglas was founded. It almost stopped Cairns from growing because it offered an easier way to the Hodgkinson goldfield. When tin was found in 1880, the road from Port Douglas was still preferred.
However, Cairns bounced back. In 1882, heavy rains closed the road from Port Douglas. People then wanted a railway from Herberton to the coast. On September 10, 1884, Cairns was chosen as the best place for the railway. This made sure Cairns would be the main town and port for Far North Queensland.
Surveying Cairns Harbour
Even though ships used Cairns from 1876, the harbour wasn't properly mapped until 1878. Before then, buoys guided ships through the channel. A lantern on shore helped ships at night.
How Hydrographic Surveys Work
Mapping the Sea and Coast
Hydrographic surveying is about mapping the seabed and coastal areas. This helps ships navigate safely. In the 1800s, this became a very specialized job in Britain.
First, surveyors created a network of control points on hills or headlands. Then, "coast liner" teams mapped coastal features and recorded high and low tide lines. They also took "soundings" to measure the depth of the seabed.
Measuring Water Depths
Large survey ships measured deep water. Smaller boats, called "chicks," measured depths closer to shore. They used a lead line to find the depth. Surveyors recorded these depths at different tide levels.
Later, these measurements were adjusted to a common "datum." This datum is a fixed reference point, like the low water mark. After a survey, the tides and datum were linked to a permanent bench mark for future use.
The Broad Arrow Mark
A bench mark is a point with a known height above or below a datum. It's marked on something strong and lasting. The "broad arrow" symbol was used from 1852 to show a government survey.
At Bessie Point, the broad arrow is carved into a large rock. It's about 50 centimetres (20 in) tall and 70 centimetres (28 in) wide. This mark is 12 feet (3.7 m) above the low water ordinary spring tides. This means all water depths on the 1878 map of Cairns Harbour showed the depth at this low tide level.
History of Coastal Surveys
Early Explorers and Admiralty Surveys
In 1770, Captain James Cook was the first British navigator to map the coast of what is now Queensland. He named Trinity Bay. The British Admiralty started its own surveys in 1795. Many navigators charted Queensland's waters, including Matthew Flinders and Phillip Parker King.
Queensland's Partnership with the Admiralty
After Queensland became a separate colony in 1859, more accurate maps were needed for its growing ports. Shipping was very important for Queensland's economy before World War II.
In 1860-61, Queensland and the British Admiralty agreed to share the costs of surveying. The Admiralty provided staff and tools, and published maps. Queensland provided lodging and transport for the staff. Their main goal was to map a safe shipping route along the Queensland coast.
In 1861, Lieutenant George Poynter Heath was appointed marine surveyor for Queensland. He later became the Portmaster. In 1862, Master James Jeffery became Queensland's first Admiralty Surveyor. He used a surveying schooner called HMS Pearl.
Continued Surveys and New Ships
Master Edward Parker Bedwell took over from Jeffery in 1866. He surveyed the coast between Danger Point and the Cumberland Islands. He also mapped major rivers like the Brisbane and Mary rivers.
Lieutenant Edward Richard Connor helped Bedwell from 1870 to 1878. Connor had worked in many parts of the world before coming to Queensland.
Connor's Survey of Cairns Harbour
In January 1878, Connor traveled to Cairns. He started surveying Cairns Harbour on February 1 and finished by February 9. He reported that Cairns Harbour was a safe anchorage. He noted that the deepest water was near the wharves. He also confirmed that he had left clear datum marks at both Cairns and Port Douglas. His map of Cairns Harbour showed water depths based on the Bessie Point bench mark.
Dredging the Harbour
Even with a safe harbour, the channel to Trinity Inlet needed constant dredging for larger ships. The depths for dredging were calculated from the Bessie Point bench mark. For example, in 1890, the channel was dredged to 13 feet (4.0 m) deep at low tide. But by 1894, it had refilled to 8 feet 6 inches (2.59 m).
The Cairns Harbour Board took over the port in 1906. By 1915, a 19 feet (5.8 m) deep entrance channel had been dredged. The material removed from dredging was used to create new land on shore.
End of the Admiralty Agreement
By the end of 1879, the Admiralty survey had reached Cape Conway. Queensland decided to stop the agreement with the Admiralty due to financial reasons. However, the British Admiralty continued its own surveys of Queensland waters. The agreement was renewed in 1885, with the Admiralty paying more. The Queensland gunboat HMS Paluma was even lent for survey work.
After Australian Federation in 1901, the Admiralty continued surveying Queensland waters until the 1920s. The Hydrographic Branch of the Royal Australian Navy (RAN) was formed in 1920.
Cairns Harbour Today
By the 1920s, Cairns Harbour started to change. The railway from Brisbane to Cairns was completed in 1924, which meant fewer passenger ships from the south. However, the port continued to export goods from Far North Queensland. It was also used as a naval base by the RAN and US Navy during World War II. Today, Cairns port is mainly a cruise ship destination and a base for fishing boats. It still exports and imports goods and is used by the RAN.
Where to Find the Bench Mark
Bessie Point is on the southeast side of Trinity Bay, east of Cairns. You can reach it by the Pine Creek-Yarrabah Road. The road goes north along Rolling Bay and then turns sharply southeast at Bessie Point.
The bench mark is carved into a large, split granite boulder. This boulder is on the Rolling Bay (west) side of Bessie Point, at the top of the beach, close to the road. The boulder is about 3 metres (9.8 ft) wide and 2 metres (6 ft 7 in) high. The broad arrow is carved into the upper half of the northwest side of the boulder. It is above the water level for most tides.
Heritage Importance
The Hydrographic Survey Bench Mark from 1878 at Bessie Point was listed on the Queensland Heritage Register on May 9, 2014.
Demonstrating Queensland's History
This bench mark is important because it shows the history of the Admiralty survey work in Queensland's waters from 1862 to the 1920s. This surveying was vital for safe shipping and for Queensland's economic growth.
The creation of this bench mark was a key step in Cairns becoming the main port for Far North Queensland. Surveying Cairns Harbour was necessary for safe navigation and for the port to develop.
Showing Survey Mark Characteristics
The Hydrographic Survey Bench Mark at Bessie Point clearly shows what Admiralty survey marks look like. It is a broad arrow carved into a large, strong object, placed above the usual water level.
