A Tower Mill is a type of windmill which consists of a brick or stone tower, on top of which sits a roof or cap which can be turned to bring the sails into the wind. It is thought to have been invented in Western Europe in the 13th century, a stone windmill being recorded at Dover in 1289. In the Netherlands windmills named torenmolens (tower mills) have a compact-built, cylindric or only slightly conical tower; all other "stone mills" such as shown on the photograph are "stone gallery / mound / etc. mills" (stenen stelling / belt / etc. molens). In the Southern Netherlands four mills of that type (Dutch definition) survived, the oldest one built in 1441. The cap of three of those mills is turned by a luffing gear built in the cap. Older types of the tower mill could be found on castles, fortresses or city walls with a fixed cap since the 14th century, and are still be found around the Mediterranean Sea. They were built with the sails facing the prevailing wind direction.
The advantage of the tower mill over the earlier post mill is that it is not necessary to turn the whole mill ("body", "buck") with all its machinery into the wind; this allows more space for the machinery as well as for storage.
In the earliest tower mills the cap was turned into the wind with a long tail-pole which stretched down to the ground at the back of the mill. Later an endless chain was used which drove the cap through gearing. In 1745 an English engineer, Edmund Lee, invented the windmill fantail – a little windmill mounted at right angles to the sails, at the rear of the mill, and which turned the cap automatically to bring it into the wind.
Like other windmills tower mills have normally four blades. To increase windmill efficiency millwrights experimented with different methods:
Therefore engineer John Smeaton invented the cast-iron Lincolnshire cross to make sail-crosses with five, six, and even eight blades possible. The cross was named after Lincolshire where it was most widely used.
In England around 12 eight-sailers, more than 50 six- and 50 five-sailers were built in the late 18th and 19th centuries, half of them in Lincolnshire. Of the eight sailed mills only Pocklington's Mill in Heckington survived in fully functional state. A few of the other ones exist as four-sailed mills (Old Buckenham), as residences (Diss Button's Mill), as ruins (Leach's Windmill, Wisbech), or have been dismantled (Holbeach Mill; Skirbeck Mill, Boston). In Lincolnshire some of the six-sailed (Sibsey Trader Mill, Waltham Windmill) and five-sailed (Dobson's Mill in Burgh le Marsh, Maud Foster Windmill in Boston, Hoyle's Mill in Alford) slender (mostly tarred) tower mills with their white onion-shaped cap and a huge fantail are still there and working today. Other former five- and six-sailed Lincolnshire and Yorkshire tower mills now without sails and partly without cap are LeTall's Mill in Lincoln, Holgate Windmill in Holgate, York (momentarily undergoing a restoration programme), Black, Cliff, or Whiting's Mill (a seven-storeyed chalk mill) in Hessle and (with originally six sails) Barton-upon-Humber Tower mill, Brunswick Mill in Long Sutton, Lincolnshire, Metheringham Windmill, Penny Hill Windmill in Holbeach, Wragby Mill (built by E. Ingledew in 1831, millwright of Heckington Mill in 1830), and Wellingore Tower Mill. Another fine six-sailer can be found in Derbyshire - England's only sandstone towered windmill at Heage of 1791.
The world tallest tower mills can be found in Schiedam, South Holland, the Netherlands with the highest mill being De Nolet (built in 2006 as a "generator mill" producing electricity and named after the local Nolet distilling family the mill belongs to, 140 ft / 42.5 metres to cap) and De Noord (The North, corn mill of 1803), 109 ft / 33.5 metres to cap) both in working order.
England's tallest tower mill is the nine-storeyed Moulton Windmill in Moulton, Lincolnshire, with a cap height of 97.5 ft / 30 metres. Since 2005 the mill has a new white rotatable cap with windshaft and fantail in place but without her four patent sails. The stage was erected during April / May 2008.