Agricultural Scenery – Floating Mills


(Floating mills on the Seine, Paris, 1310. Francais, 2092, 37v. Bibliotech National de France)

The joy or sometimes drawback, of studying history is the number of rabbit holes one can disappear into without warning,  diverting attention from the main topic of study. My current diversion is the floating flour mills, of the great rivers of Europe, from the 6th C onwards. I discovered them in a fascinating book, about the travels of  12th Century student and would be etymologist, Alexander Neckham, between England and University in Paris. I’m reading it to add depth to a local history study I’m doing,  following the fortunes of a 12th C, Southampton Merchant, Gervase le Riche, who was involved in trading fleece and wool with European merchants. One intriguing aspect of his story is a journey he undertook, to deliver his contribution towards Richard I’s ransom, in exchange for lands. I’ll share more of his story as my research progresses. During his journey Gervase, like Alexander, would have seen, and remarked on these floating mills, as a curiosity. They were not used in 12th C Britain,  and trials in the early modern period were unsuccessful (Langdon 2004).

Throughout the medieval period mills were owned by the feudal overlord of a manor, the King, a noble, barons or monastery. The peasantry paid a fee or banality to the miller to grind their grain, which he collected on behalf of his Lord. Peasants would try to avoid fees by using their own quern stones or handmills, or using the mill of cheaper, nearby manor.However as evidenced by this quote from a 12th C document, granting a mill and its rights to a local priory, this resulted in high penalties:

Wherefore no other mill, by any other man, maybe made in the said town, save by the will and concessions of the said canons. Nor may they (townsmen) have handmills. If nevertheless, anyone of the said town should refuse to come to the said mill, I an my heirs shall compel him to follow (attend) it; and if any be found attending another mill, the sack and corn shall be the canons, and the horse [carrying the same], as well as the penalty shall be to me and my heirs.

(Translation of charter, 1150, granting the mill of Silsden to the priory by Cecilia de Rumelia, Lady of the Manor of Silsden) (Bennet and Elton, 1898)

Floating mills, were also under feudal ownership and spread through Europe, following their invention in Rome, where they were invented in around 537AD. The invading Goths, smashed the aqueducts carrying fresh water to the city’s fountains, also removing the supply to the water mills, along their length. According to Procopius,the resourceful citizens, attached milling apparatus to boats and anchored them in the Tiber, building a bridge between them for access and to delivery of grain & collect flour by donkey. This provided the means to produce flour, bake bread and withstand the siege. The number of mills grew over time, within the protective city walls and finally became obsolete in the early 19th Century  (Caggia and Gwynn). The mills were versatile as they could operate under bridges, as in Paris or in open water, as  in Germany and Eastern Europe. The Parisians employed men in boats to deliver grain and collect the flour (Holmes 1952), whilst the Germans and Eastern Europeans constructed jetties between mill and shore, for this purpose (Panorama SK 2014). During floods or when ships needed to pass the mills could be towed to shore and when drought reduced  the depth of a river, one horse could easily tow one upstream, to a more favourable site.


Model of a Byzantine Ship Mill, on display at the Museum of History, Science and Technology, Istanbul, built on a similar pattern to the French design.

There appear to be 2 different designs for the mills, the simpler and more versatile one hull, pictured above, which worked as described by Holmes below:

The wheel is over the side; the millstones and operator are on a cupola shaped platform with peaked roof, which is build amidships on each hull. A ladder leads up to this. Sacks of grain are being brought in small boats and passed up to the millers. Each miller pours the grain into a funnel which is over the stone. The milled flour is pouring into sacks beneath the platform.

(Daily  Living in the Twelfth Century, Based on the Observations of Alexander Neckam in London and Paris, pp103 -104)

and the more complex two hulled ship, illustrated below, which was designed with a specific mooring in mind, and used similar technology:

800px-schiffmuehle01Schiffmuhle by H Ernst 1805

Ship mills have a key advantage over static mills, because they float the wheel is always in the correct position in water, so their operation is unaffected by  the usual range of changes in water levels, ensuring a constant supply of flour. The only restriction on their use was making sure there was sufficient clearance  between the wheel and the river bed, to prevent fouling or breakages.The mills are powered by the relatively inefficient, yet ideal for purpose, undershot wheel, designed to turn when water hits the bottom paddles (de Decker, 2010). de Decker, claims this also made them useful as tide mills, but further research is required to confirm this. Static mills, have an overshot or breast shot wheel that sits at a preset height above the river.If the river level rises significantly, the wheel becomes inoperable, so flood was a very real problem. In addition a separate water supply is needed to turn the wheel, so water is collected in a weir or millpond, at a higher elevation than the mill, and a leat is then dug to convey the water to mill wheel. Water flow and speed is controlled by sluice gates. Whilst these wheels are larger and more efficient, their use requires a specific situation and a great deal of labour in both construction and maintenance (de Decker); hence the popularity of ship mills:

Location of Ship Mills on Major European Rivers

This is not an exhaustive list and I hope to add to it as I learn more:

River Countries Dates if known
Danube Austria,
Germany, Bohemia
From 1493 to 19th C
Elbe Bohemia
Last known 1911
Garon France
Kura Georgia –
10th C to 1930s
Loire France
Marne France
Mur Austria
Rhine Strasbourg
Mainz, Koln – known as “Rheinmulen”
9th to 12th C
Seine Paris, France
Tiber Rome 6th to 19th C
Weser Germany, Bremen
(Source: Wikipedia –

However, ship mills were not without their own problems and could be potentially lethal, as described by  Caggìa & Gwynne:

The mills floating on the Tiber were at the mercy of the unpredictable river currents. A heavy rainfall in Umbria or northen Lazio would swell the river and rise the water level in Rome, while periods of continuous rain would cause disastrous floods. Often the moorings were insufficient to resist the violence of the waters and the mills would be carried off by the swift tides often with people still inside. Examples of mills crashing against bridges (causing further damage to both bridge and mill); or wedging in the arch of a bridge damming the river and thus causing the waters to rise higher have also been recorded. Moreover, the artificial barriers used to direct the water onto the wheels would make the situation worse in the case of flood by impeding the flow. Floating mills were also a hazard for rowing boats and bathers. Indeed the tradition of children diving after watermelons thrown into the Tiber on Saint Bartholomew’s day was later banned because of the number of accidents.

It is also of note, that the hull had a lifespan of 30- 50 years, due to the variable quality of construction, and constant battering from the waters. The wheels needed replacement every 10 years or so (de Decker). However it is likely that this was less costly than building and maintaining a fixed mill. In later centuries they would also become a nuisance to shipping and could not compete with the improved technologies offered by the industrial revolution.

So ship mills faded out of use between the late 18th and early 20th C, mainly because a mill moored alongside is not productive, efficient or financially viable. However trials are now taking place, with some success, in Germany, using a modern version of a ship mill to generate hydroelectric power, whilst other replicas are being used as irrigation systems for municipal parks (Wikipedia, Germany). They are also tourist attractions with museums installing replicas across the rivers of Central Europe, including this beautiful example, at the Floating Mill Museum, Koloravo, Slovakia, which includes the longest, roofed,  wooden bridge, for access to the mill, in Europe:


I would like to thank the members of the British Medieval History and European Medieval History Facebook groups, who kindly shared their knowledge with me, and gave me pointers as to sources and resources used in creating this post, many for whom English is a second language.

References and Biblioography

Bennet R, Elton J (1898) History of Corn Milling, Vol II. Simpkin, Marshall and Co Ltd, London p211

Caggia S, Gwynn P (undated) The Mills on the River Tiber, In Nerone, The Insiders Guide to Rome. [online] Accessed 16/08/2016

De Decker K. (2010) Boat Mills, Water Powered Floating Factories, Low Tech Magazine [online]

Holmes UT, Jr (1952 ) Daily  Living in the Twelfth Century, Based on the Observations of Alexander Neckam in London and Paris, The University of Wisconsin Press, London pp103 -104

Langdon J. (2004) Mills in the Medieval Economy, 1300 -1540, Oxford University Press, Oxford

Panorama SK (2016) Slovakia Document Store – The Floating Mill in Kolarovo [online] Accessed 16/8/2016

Wikipedia Germany (undated) Schiffe Muehle [online]  Accessed 16/8/2016


Agricultural Scenery – Floating Mills

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