World's Oldest McNaught Beam Engine - Historic Engineering Marker Hobart, Tasmania, Australia
By Team MavEtJu on 12-Oct-15. Waypoint GA7578

World's Oldest McNaught Beam Engine - Historic Engineering Marker

In September 1990, the engine which was built in 1854 by A & W Smith & Co, then of Paisley near Glasgow, was put on display at the Hobart Technical College (now the Hobart Institute of TAFE).

In 1955 after a century of working, the engine was removed from Risby's Mill and placed into storage for some 35 years in the Department of Main Roads Plant Depot at Moonah.

The engine is a McNaught Compound Engine weighing some 25 tonnes and the flywheel alone which is 3.7 metres in diameter weighs 9 tonnes. The placement of the two double acting cylinders, one on either side of the central column, was the subject of a 15 year patent taken out by McNaught in 1845.

Most early compound engines had the two cylinders positioned on the same side of the column, but the addition of the high pressure cylinder, to an engine designed only for low pressure use often resulted in overstressing of the beam. William McNaughts arrangement avoided this problem. In other respects, the engine is somewhat similar to other early engines and incorporates the parallel link motion which was patented by James Watt in 1784.

From the records of boiler inspections which commenced in 1885, it is known that at this time, the engine was operating in Henry Clark & Co's Sawmill in Collins Street, Hobart, this business was later bought out by Risky Bros in 1921. In July 1872 The Engine.' (UK) reported on the manufacture by Mr. John Clark of Hobart Town of a boiler for a 20 hp McNaught engine used to drive a flour mlll, however, details of ownership and location are uncertain. Henry & John Clark were the sons of Alexander Clark, a prominent engineer in the Colony.

Following upon the Institution of Engineers, Australia Engineering Heritage Conference held in Hobart in October 1992, further enquiries were made overseas by Prof. Angus Buchanan, Director of the Centre for History of Technology at the University of Bath, who was the keynote speaker at the Conference, and Dr. Peter Milner of the University of Melbourne.

As a result of these enquiries and based upon information contained in the publication The Industrial Archaeology of the Steam Engine of which Professor Buchanan was co-author, it appeared that the Hobart engine could be claimed as the World's Oldest Extant McNaughted engine. The oldest existing engine of this type in Britain was built in 1865. In May 1994, the Newcomen Society of London, the World's leading authority on such matters, confirmed this claim.

This engine is therefore of great historical interest, unfortunately little is known of the history of the engine prior to 1885; and its original use and date of arrival in Australia are a mystery. It is known, however, that Alexander Clark, arrived in Van Diemares Land (Tasmania) in late 1832 and set up his own engineering business in 1838 which included both an iron foundry and workshops together with the importation of machinery. It is therefore considered most likely that he imported this engine.

Contents of the plaque:

This compounbd expansion steam engine incorporates high and low pressure cylinders places on opposite sides of the central column in accordnace with the 1845 patent of William McNaught. It was manufacturered in 1854 by A&Q Smith of Paisley, Scottland and probably by prominent local engineer Henry Clark. After 100 years of service the enigne was removed in 1955 from Risby's Sawmill in Collins street Hobart and placed here in 1990.

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For more information, please see the nomination PDF at the Heritage Register at the Engineers Australia website: Nomination