No fewer than 52 (!) water mills were needed to dry the Schermeer. In each thatched mill, type octagonal inner porter, there was a huge paddle wheel of six meters in diameter. This allowed the polder water to be pumped up about one meter, the so-called head.
Thanks to the sails, the miller was able to respond to the volatility of the wind force. And by turning the hood he could follow the wind's shrinking and clearing. Because the better he could use the wind, the more water he could pump up.
The rods (the base of the wing cross), the shaft and the paddle wheel were all made of wood at the time. That material had a limited lifespan and resulted in a high cost item. Fortunately, various technical improvements have been made over the centuries. The wooden rods and upper shafts have been replaced by (cast) iron ones. From 1850, a start was made on what turned out to be the most important improvement: the shovel wheel through an auger – a large-scale project that took a total of 25 years to complete.
The technology stood for nothing…
Thanks to this innovation, the three-stage drainage (with paddle wheel) of the inner atriums was replaced by a two-stage drainage (with auger). A test with the current Museum Mill showed that the head of an auger was so much greater than that of a paddle wheel: the dewatering could be carried out with two mills – one stage – less. And because the augers worked so well, the switch to steam dewatering was postponed. In addition, wind dewatering – according to a report from 1876 – was much cheaper than steam dewatering.
Because wage costs continue to rise and the Working Hours Decree of 1915 limited the working hours of the millers, the polder board decided in 1924 to switch to electric drainage. The biggest advantage was of course that they were no longer dependent on the wind. And so it was that in 1929 the last mills were decommissioned. From then on, the water in the polder was maintained by three electric pumping stations (Emma, Juliana and Wilhelmina). Many decades later – at the end of the last century – these were replaced by two computer-controlled electric pumping stations, which are called Beatrix and Willem-Alexander according to current tradition.
They're just tools...
Because the mills were 'only' tools, it was decided in 1929 to sell them individually as soon as they were no longer usable. Lucky accident: in the Second World War, some mills were made ready for use again in case of emergency – which they did. After that, the water board had to keep a number of mills operational in the early 1950s – thanks to the Protection of Water Management Works in Wartime Act (Wet BWO). Two mills were also preserved in the context of the housing shortage. In the end, 11 icons were preserved, of which 6 can still be used for the drainage of the polder. Just like 400 years ago.