McNaught Beam Engine, possibly world's oldest, Hobart
Background
The worlds oldest McNaught Beam Engine. Owned by the Tasmanian Museum & Art Gallery on static display at the Bathurst Street entrance to the Hobart Institute of TAFE.
This compound expansion steam engine incorporates high and low pressure cylinders placed on opposite sides of the central column in accordance with the 1845 patent of William McNaught. It was manufactured in 1854 by A&W Smith of Paisley, Scotland and probably imported by prominent local engineer Henry Clark. After 100 years of service the engine was removed in 1955 from Risby's sawmill in Collins Street Hobart and placed here in 1990.
Compound engines
Most early compound steam engines had the two cylinders positioned on the same side of the column, but the addition of a high pressure cylinder to an engine designed only for low pressure often resulted in overstressing of the beam. William McNaught's 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 1794. The oldest existing engine of this type in Britan was built in 1885. However little is known of the history of this engine before 1885.
The nomination for the Engineering heritage recognition was largely driven by Fred N Lakin. Link to more detail can be found at the following link. Worlds oldest extant McNaught Beam Engine
Engineering Heritage Recognition Program
| Marker Type | Historic Engineering Marker (HEM) |
| Award Date | 1997 |
| Prominent People | Fred N Lakin |
| Nomination Document | Nomination document |
