paddlesteamers.info : The Internet's leading website for
Side-Wheeled Paddle Steamers
Paddle Steamer EnginesHere 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
https://www.youtube.com/watch?v=_dNSyEmp64oAbove : 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 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 above is from
PS Pirna which operates on the River Elbe
out of Dresden, Germany .
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)
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
PADDLERS WITH STEAM TURBINE ENGINES :
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 Return to Homepage
