Cohen & Associates Land and Aerial Surveyors

Cohen & Associates Land and Aerial Surveyors Land and Aerial surveyors based in Launceston, Tasmania operating statewide including Flinders Island and King Island.

Cohen & Associates Pty Ltd has operated throughout Tasmania in all aspects of surveying since being established by well respected surveyor John Cohen in 1946. Cohen & Associates Pty Ltd is owned and directed by Adrian Fairfield, a Registered Land Surveyor and RPAS Pilot. We maintain a permanent office in Launceston and provide a full range of land and aerial surveying and planning consultancy serv

ices throughout the State. We make regular visits to Flinders Island and can assist with any surveying and subdivision matters on the Island.

Fishers Sugarloaf: Sprent’s Observations, 21st September 1852 The exact origin of the name remains a mystery, but an int...
19/06/2026

Fishers Sugarloaf: Sprent’s Observations, 21st September 1852

The exact origin of the name remains a mystery, but an intriguing theory appeared in the Daily Post on January 25, 1912:

"On one side is a high conical shaped eminence which bears the soubriquet of Fisher's Sugar-loaf. Who Fisher was no one seems to rightly know, but rumour hath it that he was a 'gentleman of the road' and that he frequented the Sugar-loaf when he wished to hide himself from persons in uniform who desired to form a closer acquaintance with him."

This is supported by newspaper articles from the era confirming a bushranger named Fisher was operating in the area during the 1840s.

While Fisher may have used the peak to hide, James Sprent made use of the natural feature in his survey. Fortunately, Sprent's 1852 field book provides excellent detail regarding the eccentric instrument station and his measurement of the object, which he described as a "very crooked and leaning tree." 🌳

Today, the instrument's location is clear on a high rock with a level surface perfectly suited for a theodolite, right alongside the charred remains of Sprent’s original tree. An old bottle and tin were even found at the site—could they have belonged to Fisher, Sprent, or later survey crews? 🧐

The site includes the remains of a crude trig station, possibly left by early HEC (Hydro-Electric Commission) surveyors working on the Great Lake hydro scheme and the nearby Waddamana power station.

The land itself has an incredible historical link to the HEC: it was once owned by Alexander McAulay, the prominent mathematician and University of Tasmania professor whose pioneering work led to the state's first major hydroelectric power station. ⚡💧

Now known as Barren Tier, previously referred to as Barren Plain Tier by James Sprent and not to be confused with Barren...
17/06/2026

Now known as Barren Tier, previously referred to as Barren Plain Tier by James Sprent and not to be confused with Barren Tier west of Mole Creek.

Sprent 28th Sept 1852 "The object upon this point is a pyramid 8ft square and 20 3/4 feet high filled about 4 feet with stones."

A detailed description of a typical pyramid of wood is contained in Sprent's letter to Major Cotton 1852.

“The objects I have put up lately have been made of 8 feet square at the bottom. The logs crossing each at one foot from the end leaving the interior space six feet clear. I work these up to 8 feet height, then I use 6 feet logs and work these up to 14 feet high. Then I use 4 ft logs and work these up to 16 or 18 feet above ground, generally to the later height. ". See generated sketch.

The trig site is located on a prominent rock and was later renewed by the Hydro Electric Commission surveyors and later replaced by a fire lookout cabin.

The 1940's photo taken by Tom Andrews HEC worker at the time and based at Shannon is a great example of an early trig made from available materials. The stones at the base would be from Sprent's trig placed over 90 years earlier.

Mt Zeehan. Surveyor General E.A. Counsel was well aware of the difficulties in making astronomical observations on the W...
13/06/2026

Mt Zeehan.
Surveyor General E.A. Counsel was well aware of the difficulties in making astronomical observations on the West Coast. In his parliamentary report in 1900, he recalled that in 1894, "I recorded 283 nights when the sky was totally unfavourable for meridian observation, and 2 nights when partially obscured, leaving a balance of comparatively a few nights suitable for the purpose named, and these nights were confined chiefly to one term of the year."

Soon after Mt Zeehan had a trig station as described in the Journal and Papers of Parliament, Vol. 1902. The work was completed by the recently arrived surveyor from New Zealand, Robert Barr Montgomery.

"...the vanes and fastenings have come to hand for the trigs; the masts on Mt Zeehan, Agnew, Dundas, and Tyndall are now fully equipped with vanes and fixed plumb over plugs bedded in solid rock, being steadied by guy ropes attached to an iron collar on the mast and fixed to the ground with eye-pins through which the guy ropes are attached with a screw end, the whole being arranged to ensure easy adjustment of the mast in a vertical position after the observations at each point are taken, and while the cairns are being built at the close of operations. Operations on Mt Murchison were abandoned in a snow storm."

Could the rusty steel plug with brass inset in solid rock be the original mark placed by Montgomery?

Billopp Bluff and its 3 cairns. Two can be accounted for... but the third is a mystery! The Oldest (Large Southern Cairn...
07/06/2026

Billopp Bluff and its 3 cairns. Two can be accounted for... but the third is a mystery!

The Oldest (Large Southern Cairn):
Constructed in 1937 by Army surveyors working on the ‘Evandale’ 1:63,360 map. This covered a massive 1,500 square kilometre military training area between Longford and Campbell Town.

The Northern Cairn:
Built by Hydro Electric Commission (HEC) surveyors in the mid-1950s. Surveyor Ken Carton headed up via the cliff with a team of 9 to place the mark and build the trig station (which used to include a white-painted timber tripod). According to Snow Smith, it was a tough climb for all but especially the crew who were on their last day with the gang and had been drinking the night before! 🍻 (Via 'Tickleberry Tales and other stories from the people of the Hydro' by Heather Felton).

The Mystery (Small Southern Cairn):
Its origin is unknown. Given its location and limited visibility, it wouldn't have been much use as a trig station.

Does anyone know the story behind this third cairn? Let us know below! 👇

Wentworth Hills trig station in Central Tasmania. Lower order station observed by Sprent in 1850's. The mountain later p...
04/06/2026

Wentworth Hills trig station in Central Tasmania. Lower order station observed by Sprent in 1850's. The mountain later proved a great location for the Hydro Electric Commission surveyors. The rotten remains of a basic timber trig station pyramid found. The remaining timber spar 5m in length included heavy duty copper wire securing multiple supports. The top section included multiple copper wire loops that may have held a flag. Sample generated image included to help demonstrate this style of Sprent station. I wonder how old these remains are and who built the strucutre?

Hardy is a name often mentioned by bushwalkers and surveyors in Tasmania but who is he?Wentworth Marmaduke Hardy, born i...
29/05/2026

Hardy is a name often mentioned by bushwalkers and surveyors in Tasmania but who is he?
Wentworth Marmaduke Hardy, born in Auckland, New Zealand, in 1846, was educated in England and France. His surveying career commenced with the Survey Department, South Australia, in 1865. In 1870, he was appointed as a draftsman, and his skills in that field are obvious. In 1878, he started his role as a trigonometrical surveyor.

He moved to Tasmania and was appointed Inspector of Surveys in 1884, a position he held until 1899. His appointment came at an important time, when the first known regulations guiding the practice of surveys of land had only just been issued.

Serious about his role he didn't take long to ruffle a few feathers. His 1886 report regarding Inspection Surveys included:

"The work of one district and one authorised surveyor were found on my field inspection both to be abominably bad, badly executed, and by one of them deliberately falsified; in the other case inaccuracy was caused either by gross carelessness or sheer incompetency."

Between 1889 and 1906, he worked as a District Surveyor before moving back to South Australia until his death in 1919.

He completed surveys on Flinders Island between 1889 and 1890, and commenced a trig network that was never completed. His early surveys noted the limestone soils, stating the land would be well suited to growing claret and table grapes. He surveyed a block of land for his wife, Marion, near the outlet of the Samphire River, but he didn't stay. He did leave his mark with cairns but also being the first to document Butchers Peak. We can't be sure, but it looks like a butcher's block on a tall rocky cone.

Hardy is best known for his distinctive stone cairns. Based on his description, they are nine feet in diameter and stand about seven feet high, then taper to a diameter of three and a half feet and an overall height of ten to eleven feet. A central pole, about fourteen feet long, was carefully lowered down a central well and firmly set in place. At the base is a large stone or solid rock with a cross within a circle and a broad arrow punched with a cold chisel.

An interesting description from a cousin noted Wentworth's time in South Australia later in life:

"Wentworth was a source of constant enquiry to me as he was often living at Payneham Road. In general I found him immensely intriguing! Nobody would divulge who he was! But I thought he was a cut above them all! He behaved in what I would still call a ‘foreign’ manner. His wine toasts were usually in French and he dressed in a sort of frock coat and wore nice gloves and had an air of ‘savoir faire’, despite Burton’s stricture that he was an insufferable bore."

He was a colourful character but one who played an important role improving the surveying profession and surveys of land in Tasmania.

Special thanks to the late Bob Wyatt, who spent many years researching Hardy and accumulating an impressive collection of information.

Have you heard of a Laplace Station? And did you know that in 1937, the ABC snuck a time signal into their radio broadca...
22/05/2026

Have you heard of a Laplace Station? And did you know that in 1937, the ABC snuck a time signal into their radio broadcasts to assist Army surveyors burning the midnight oil at Nile?

In 1937, a decision was made to produce a 1-inch-to-1-mile ‘Evandale’ map of the military training area, covering 1,500 square kilometres between Longford and Campbell Town. For possibly the first time in Tasmania, aerial photogrammetry was used to map features and contours. This new technology was set to replace ground-based "plane tabling" as the primary method for creating topographical maps. Following the success of this project, a program to photograph the entire state commenced in 1945, though it wouldn't be fully completed until 1951.
The aerial photos for the Evandale map were captured by the RAAF. On the 17th of February 1937, Major Vance, WO2 Johnson, and survey assistant Hicks arrived on the ground. They were from the Royal Australian Survey Corps (RA Svy), one of the principal military survey units in Australia. Their role was to provide the maps, aeronautical charts, hydrographic charts, and geodetic data required for land combat operations.
The small crew made an immediate start on the reconnaissance: clearing vegetation, repairing existing trig beacons, and constructing new ones. These Army beacons had a unique design that set them apart from earlier ones built by Sprent and Hardy. They featured a ground mark buried up to 18 inches deep, covered by a large stone cairn (about 2.5m wide and 2m high) supporting a 12-foot hardwood pole fitted with iron discs.
Because there was some doubt about the accuracy of the existing geographical network, the decision was made to establish a new origin point. The accurate latitude and longitude was calculated based on astronomical observations at a common point with the trigonometrical network, which is known as a Laplace Station.
Remarkably, the Laplace Station at Nile was marked using a 30mm shell casing set in concrete. It was buried just deep enough to survive nearly 90 years of farming activity, serving as the official origin point for statewide mapping all the way until 1966.
The astronomical observations required taking a series of measurements to the stars at highly precise times. To make this possible, the ABC broadcast a special time signal on the radio at 8 PM and 11 PM each night while the surveyors made their observations.
WO2 Johnson was tasked with performing the complex network calculations. To ease the massive workload, he relied on another piece of cutting-edge technology: a Brunsviga 20 mechanical calculating machine.
It was an incredible effort—one that truly signalled the start of the golden era of topographical mapping in Tasmania.

Mt Boyes, Flinders Island named after George William Boyes, an early settler. George assisted John William Brown during ...
18/05/2026

Mt Boyes, Flinders Island named after George William Boyes, an early settler. George assisted John William Brown during his 1887 survey of Flinders Island.

Surveying ran deep in the Boyes family. George’s younger brother, Frank Henry Boyes, was a well-known surveyor who worked between 1882 and 1932, spending 40 years living on Flinders Island. Additionally, their uncle, William Lukin Boyes, worked as a surveyor in Tasmania from 1856 to 1862.

The Department of Lands and Surveys placed the first official survey mark on the mountain in 1953. In 1981, after the original timber structure was found destroyed, it was replaced by the steel beacon.

However, the mountain can be a navigational trap. Depending on the viewing location, the apparent peak shifts between multiple points. Early surveys generally took their observations to the "central k**b" a prominent rocky outcrop located approximately 55 meters northeast of the trig beacon. To add to the confusion some 'modern' surveys alternated between the two features.

Legges Tor revisited to confirm the location of F. Smithies photo 30th August 1925 showing the possible cairn built by C...
10/05/2026

Legges Tor revisited to confirm the location of F. Smithies photo 30th August 1925 showing the possible cairn built by Colonel W.V. Legge 1907.

Given the history of the peak and it's actual height the visit provided a great chance to run the 1870's Casella hypsometer.

The hypsometer was an ingenious solution that operates on a fundamental principle of physics: the boiling point of water drops as atmospheric pressure decreases and that the barometric pressure varies with the height of the point of observation.

The boiling point of 203.32 F once atmospheric corrections applied indicated a height of 1,571m. A great comparison to the GNSS height of 1,573.1m.

What’s in a name? In Tasmania, getting it wrong could cost you $$$.Until the 1950s, we didn't have the luxury of accurat...
07/05/2026

What’s in a name? In Tasmania, getting it wrong could cost you $$$.

Until the 1950s, we didn't have the luxury of accurate topographic maps or a rigorous system for managing place names. Walking clubs and local councils played a prominent role in naming places. To fix a landscape full of confusing duplicates, the Nomenclature Board was established in 1953, which was later replaced by Placenames Tasmania in 2020.

Why so strict? Consistent names are crucial for navigation, safety, cultural heritage, and administration. In fact, misrepresenting a place name can land you a fine of up to $4,100 (plus $410 a day!).

But don't worry, the law has a sense of humour—it officially allows for "comedic" or "colloquial" names, as long as they aren't actually misleading.

Before consistent place naming protocols, surveyors had to make do with limited information and local knowledge. This lead to confusion but also names are sometimes revised for safety or historical reasons:

Mayday Mount to Mt Beecroft: Named "Mayday Mount" in 1827 by VDL Company surveyor Joseph Fossey, the title stuck for almost 160 years. But as air traffic and visitation in the area increased, having a mountain named "Mayday" caused obvious confusion on emergency radio channels! It was renamed Mt Beecroft in 1985. The new name was proposed by the Launceston Walking Club in honour of George Beecroft, a trapper who worked in the area at the turn of the 20th century.

Sprent's Obelisk to Federation Peak: Originally called the "Obelisk" by surveyor James Sprent, this iconic peak was officially renamed Federation Peak in 1901 to celebrate the new Federation of Australia.

Next time you are viewing an old survey plan or exploring Tasmania, remember: the name on a signpost isn't just a label—it's a piece of history!

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Launceston, TAS
7250

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