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Paddle Steamer Engines
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Here is a good illustration of paddle steamer engines and their attached paddle wheels. This set comes from the River Danube paddle tug Vertes (ex-Tihany) which operated from 1914 until 1963 and which are now displayed in the grounds of the Budapest Transport Museum. Photo kindly supplied by Zsolt Szabo
How does a paddle steamer engine work?  Put simply, water is heated in a boiler until it evaporates, producing steam. The steam is transferred through pipes into a cylinder where it expands under pressure to push a piston in the cylinder. This provides the motion which is transferred from the piston to a drive shaft (crank) which turns the paddle wheels. The task is then to ensure that as much power as possible is obtained from as little fuel as possible in the boiler. Throughout its history the steam engine has evolved with engineers discovering and incorporating more efficient means of achieving their objectives at each stage of the process. Probably the most important early development was the condenser which returned unused steam to water but also allowed for other efficiencies in the cylinders. The compound engine, which used the residual pressure of steam after it had pushed the cylinder's piston to repeat the task in a second "low pressure" cylinder increased efficiency further. The triple expansion engine was a further development, where the steam was used three times, although this was reasonably rare on lake and river paddlers. Common for deep-sea (screw driven) vessels, even quadruple expansion was used on the largest of ships. The precise design of the cylinders also evolved over time, with so-called oscillating cylinders eventually replaced by fixed, diagonal-lying cylinders being the preferred configuration in paddle steamers. Boilers themselves were subject to continuous design improvements, especially as iron was replaced by steel as a stronger material and the properties and reliability of steel improved over time. This allowed steam to be delivered to the engines at higher and higher pressures.
    Excursion steamer operators were no different to other commercial organisations. Cost reductions were continuously sought with the most modern technologies normally chosen for new vessels.  In the late 1920s, the marine diesel was coming to prominence in Europe and from the late 1920s onwards, no paddle steamers were built except for smaller units for service on the narrow River Vltava around Prague and large vessels for the serving the long, wide rivers of the Soviet Union. Lake Geneva's paddle steamer Geneve, then only 38 years old had her steam plant replaced by a diesel-electric unit as early as 1934.
One notable exception was Britain, where paddlers were built in substantial numbers and even three large new paddlers were built shortly after World War II with steam engines (Waverley, Cardiff Queen and Bristol Queen). They were a result of the conservative engineering policies of their owners, the relative cheapness of coal and the need to use familiar designs to obtain these ships quickly to make good wartime losses.

Paddle steamer engines now remain mainly as a curiousity, for their own sake, as historical relics reminding us of a proud engineering heritage. Most people who see them do marvel at these magnificent pieces of machinery and they add something special to the excursion experience. 
To see a paddle steamer engine in operation and its working explained in detail by its engineers, this video is essential viewing

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Above : Many paddle steamers have helpful interpretative displays to help passengers understand how their engines work. A good example is PS Unterwalden on Lake Lucerne which has its panels attached to the railings from where the engines can be seen


An older design principle, the oscillating engine, which was obsolete technology by the end of the 19th century is still to be found in operational service in the 21st century ! The set seen above is from PS Pirna which operates on the River Elbe out of Dresden, Germany .

Click here to see photos of the engines of many of Europe's active and statically preserved paddle steamers

Several examples of paddle steamer engines have been preserved and are available for public viewing. One of the finest examples is that of the former Lake Lucerne paddler Pilatus, displayed at the Verkehrshaus, the Swiss National Transport Museum at Lucerne (above)

Click here for more about engines preserved in museums or private collections.


All "modern" paddle steamers have been built with diesel engines, but one older steamer, PS Montreux (1904) on Lake Geneva received an entirely new set of twin-cylinder diagonal engines when she was re-converted back from diesel to steam in 2001. Her owners had hoped to convert their three other "conversions" back to steam but this was later ruled out on financial grounds and the fact that Sulzer, who had been involved in the new design finally closed its related manufacturing operation. 
See more of these engines

PADDLERS WITH DIESEL ENGINES : Diesel-electric, diesel-hydraulic 

Paddle-wheel ships, even if not powered by steam engines, do have their attractions, at least from the shore. Watching them pass by or call at a nearby pier, there is nothing to distinguish them from the real thing. On board, it is a different matter. These vessels have enclosed engine rooms and therefore, very little of interest to view on the main deck. The smooth operation of steam engines is replaced by the constant din and vibration of diesels, more noticeable on some vessels than others. Very few paddlers have been built as motor vessels outright - the Stadt Passau and Stadt Wien twins for DDSG on the Danube were rare examples. In more recent times, those which have been built have been motor ships, both sidewheelers and the more common "Mississippi nostalgia" style sternwheelers. A number of ships have been converted from steam to diesel-electric or diesel with hydraulic transmission over the years, starting with Lake Geneva's PS Geneve in 1934. Although this could be regarded as an economy measure, it has only generally happened when there has been a majotr issue with the steam plant, such as the need for a new boiler. There is, of course, the hope that at some stage they might be reconverted, as was the case with PS Montreux on Lake Geneva but these would be exceptional cases : plans to return the remaining three Lake Geneva vessels to steam faltered on cost grounds, as did the hopes of retro-fitting the original engines of MPV Diessen when it was rebuilt in 2006.

Above : Engines of Grof Szechenyi (ex-Stadt Passau). Photo by courtesy of Zsolt Szabo 

Click here to see the engines of MPV Geneve, the Lake Geneva steamer regarded as the first diesel conversion when her steam plant was replaced by diesels in 1933/1934. Although she has been out of service for many years, these engines will still work if required

Dordrecht turbine engine

Steam turbines became the dominant type of marine steam engine for most applications very quickly after they were first demonstrated on a commercial ship by TS King Edward in 1901. Working on propellor shafts, it was not clear how they could be adapted to paddle steamers with their transverse crankshafts and geared accordingly. Their use was investigated and put to experimental use in four tugs, including the Dordrecht whose turbine is shown above courtesy of Felix Brun/Alstom Archives, but the arrangement was not developed for further use. Turbines did not find favour with screw propelled tugs either.  No examples remain in preservation.

Click here for more about paddle tugs with turbine engines

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