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Paddle Steamer Engines
Vertes engine.jpg
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. Perhaps the most important was the development of 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. 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 Britain, three large new paddlers were built shortly after World War II with steam engines (Waverley, Cardiff Queen and Bristol Queen) and whilst they incorporated the best engineering practice, they were a result of the conservative engineering policies of their owners. In the late 1920s, the marine diesel was coming to prominence in Europe and by 1930 had totally swept all before it. Even in Switzerland, where numerous steam paddlers have been retained, PS Geneve, then only 38 years old had her steam plant replaced by a diesel unit as early as 1934.
    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. 

Unterwlden engines.jpg
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 (see picture above)

For screw steamers, the principle is the same although the engines are arranged vertically and act on one or more shafts located close to the bottom of the ship and running along the length of the rear ship to the screw(s) at the stern.
Turbine steam engines became popular after 1901, mostly for larger vessels including short sea ferries, ocean lines and military vessels. They found application in excursion steamers on the Firth of Clyde in Scotland and a brief description of this method of propulsion is to be found in our associated website the
Clyde Turbine Steamers.

 PADDLE STEAMER ENGINES PHOTOGRAPH GALLERY

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 left is from PS Pirna which operates on the River Elbe out of Dresden, Germany ........ and it is not the only paddle steamer in the Dresden fleet so equipped !

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.


A MODERN PADDLE STEAMER ENGINE !


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. Nevertheless we now have one example of "modern" paddle steamer engines.
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 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


PADDLERS WITH STEAM TURBINE ENGINES : Tried but never followed through
Steam turbines became the dominant type of marine steam engine very quicly after they were first demonstrated on a commercial ship by TS King Edward, a famous excursion steamer on the Firth of Clyde, which sailed from 1901 to 1951. The Clyde was almost unique in the way turbines were adopted by the local fleets, as other excursion ship owners, with limited experimental exceptions, remained with tested technologies until the arrival of the marine diesel. Nevertheless, turbines quickly replaced reciprocating engines on short-sea and deep-sea vessels. Since these ships had long since abandoned paddle propulsion, turbine steamers were exclusively screw steamers ....... with a limited number of important and relatively unknown exceptions. Whilst turbines offered a number of advantages, it would appear that the rapid development of motor ships stifled further development and in terms of paddle steamers, diesel-electric and diesel-hydraulic systems were regarded as the technology with the best future, although the more simple motor and screw was the real future for most marine applications.





Turbines were fitted to three experimental paddle tugs built for use on the River Rhein in the mid 1920s and one on the River Rhone, but it never caught on and as far as the webmaster knows, was not attempted elsewhere. The above photo and drawing show the turbine and reduction gear fitted to the tug "Dordrecht". Photo courtesy of Felix Brun /Alstom Power (successors to Brown Boveri) archive.

The tugs were :

PT Zurich (1922) : Escher Wyss (Zurich)
PT Dordrecht (1925) : Schiffs- und Maschinenbau Gesellschaft (Mannheim) / Brown Boveri Company
PT Toulon (1929) : Sachsenberg / Parsons
PT Rhone (1931) : Escher, Wyss (Zurich)



Above : Rhine turbine paddle tug "Dordrecht" at Kaub. Photo courtesy of Felix Brun / Alstom Power archive

The ship was built for Dutch owners and with collapsable funnels so as to be able to sail beyound Basel in Switzerland. She was one of the longest Rhine tugs at 77.81 metres and was 22.20 metres in breadth. Steam was fed at 300 degrees celsius from twin Scotch boilers to two turbines, one high-pressure, the other low. There was one reverse turbine. The turbines generated 1500 ships horse power. Double reduction gearing reduced the revolutions from 3600 to 38. Reboilered in 1954 she was withdrawn in 1957, parts of her boiler reused in another vessel and the forward part of her hull used as a clubhouse for the Seafarers-Club at Bonn  
   

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