The first crane of this design was built in La Spezia, Italy in 1876, with others in Taranto and Pozzuoli in Italy; Mumbai, India; Malta (like India, at that time a part of the British Empire); Liverpool, UK; and two in Japan. All but the Venice crane, commissioned by the Italian Navy in 1883, have now been lost, with the La Spezia crane being dismantled in 1992. EF Clark, past president of the Newcomen Society, the British organisation devoted to the study of engineering history, visited the crane, and explained the importance of Armstrong’s innovations.
The Venice Arsenale Armstrong Mitchell crane, viewed from the rear, and showing the machinery housing
Clark related that Sir William Armstrong was a solicitor, with an interest in engineering. He worked for the Newcastle Water Company, in the north of England, in 1846. He noticed that the water mains pressure in the hilly area was particularly high, and proposed that this be used to power a planned dockside crane, rather than using a steam engine. This was the world’s first hydraulic crane, and launched Armstrong’s career as an engineer.
Armstrong went on to develop further cranes in the UK, including one at New Holland on the river Humber, in 1850. On this flat site, there was insufficient water pressure to power a crane. To tackle this problem, Armstrong invented an accumulator tower, consisting of a 300ft high cylinder with a weight at the top, pressurising the water within. This development led Armstrong to establish a factory in Newcastle, producing hydraulic systems and cylinders.
At this time, armies around the world still used muzzle-loading cannons as their sole form of heavy ordnance, despite the development of rifling for small arms. Armstrong saw that the cylinders could be used for a new type of rifled, breech-loading, artillery. This led to him building increasingly large guns to supply Britain’s imperial armies.
This development now fed back into his role as a pioneer of crane technology. The guns he was building were now so large that they needed to be lifted on board with 150t-capacity cranes. While his hydraulic cranes were powerful enough to lift these loads, the wrought iron chains then in use (before the development of Bessemer steel and wire rope) were not reliable enough to lift them, without needing frequent and costly repair and inspection. To tackle this, Armstrong built a new crane, with a hydraulic lifting cylinder connected to the jib at one end, and the load at the other. This design was used for about 15 years, before being made obsolete by the development of modern wire rope.
The jib end of the Venice Arsenale crane, showing the 160t capacity fixed lifting cylinder, and the auxiliary 40t capacity wrought iron chain.
The crane in Venice Arsenale, built in 1885, demonstrates all of these innovations. Hydraulic power was used to slew the crane, and to provide power to a 160t capacity fixed hydraulic lifting cylinder on the jib, augmented by a smaller winch and chain. Despite its importance to engineering history, it has been neglected for decades—Clark has evidence suggesting that the piston was removed from the lifting cylinder at some time in the 1940s. It is in serious need of repair.
Venice in Peril is currently working with engineers to assess the damage to the crane, and to plan its restoration. As the crane will never lift a load again, the group initially proposes to reduce the ballast to a level sufficient just to support the weight of the crane itself, without collapsing into the lagoon, and to carry out urgent repairs to rusting sections of the structure.
The project is supported by the Orient Express travel company, but is in need of additional funds. Overall, the project is expected to cost more than E900,000 (£560,000), with the initial inspection and emergency repairs costing around E134,900 (£85,000).
