Windmill

Windmills are large buildings functioning as gristmills, fulling mills or winepresses, among other sorts of cam-driven refinement structures. Though more expensive than water-driven mills, they're able to perform in regions where there is too little water, where rivers freeze, and in flatlands where the flow of a river is too slow to provide the required power. The mechanical power provided is sufficient to allow the windmill to replace water-driven mills of all varieties, with a comparative capacity for production. The number of persons operating the windmill depends on what products are made — in that regard, the number of residents resembles that of other mills.

A windmill's efficiency depends on wind conditions, requiring steady airflow to maintain operation. In areas with inconsistent winds, windmills are often built taller to capture more stable air currents. The mechanism inside transfers the wind's rotational energy through a system of gears and shafts, enabling the mill to grind grain, full cloth or press materials such as oilseeds. The sails, made of wood and cloth or slatted boards, are adjusted to control speed and efficiency. Unlike water mills, which rely on continuous water flow, windmills require monitoring to ensure they are turned into the wind for maximum effectiveness.

In some regions, windmills serve additional purposes, such as pumping water for irrigation or drainage. These variations, commonly found in low-lying areas, use mechanical suction to draw water from marshes and lowlands, making land more viable for agriculture. The adaptability of windmills makes them indispensable where water power is unreliable, ensuring that production remains steady despite seasonal or geographic limitations.

Construction

"Tower mills" are the prevalent form, consisting of a wooden or brick tower on which sits a wooden "cap" or roof. Four blades are attached to a "windshaft" that turns machinery inside the mill; these blades are cloth-covered to grip the wind. This cloth needs to be manually removed in storms to protect the arms from damage, or the amount of sail needs to be adjusted depending on the amount of wind. A gallery around the upper part of the mill allows access to the blades.

The windshaft is connected by gears to a vertical shaft inside the mill that can be used to drive a millstone or be further connected by other gears in order to run a horizontal cam-shaft or winepress. A large space exists at the bottom of the mill, usually built outwards to protect stores from the rain; this space is used for storage for materials that are both processed or waiting to be processed.

By 1650, tower mills are widespread across Europe, with improvements in construction allowing for greater efficiency in wind capture and mechanical power transmission. The cap of the mill, which holds the windshaft, is built to rotate so the sails can be turned into the wind. In many regions, this rotation is controlled manually using a tailpole and wheel mechanism, while more advanced mills feature an internal gear-driven system, allowing for easier adjustments. Mills in coastal and flatland regions are built taller to take advantage of stronger and steadier upper winds, while those in hilly areas may be shorter and positioned strategically to maximise exposure.

The materials used in construction vary by region. In the Netherlands and parts of Germany, brick and stone towers are preferred for durability, while in England and France, timber-framed mills are still common, especially in areas where stone is costly. The blades are traditionally constructed of oak or fir, with canvas or sailcloth coverings that can be reefed or extended to control wind resistance. Some mills are designed with spring sails, allowing for automatic adjustment based on wind speed, reducing the need for constant manual oversight.

Inside the mill, the workspace is divided into multiple levels, each serving a different function. The upper floors house the main gears and windshaft connection, with the grinding mechanism positioned directly beneath. The lower levels provide space for storage, drying grain or staging materials for processing. Many mills also include living quarters or a small dwelling attached for the miller and their family, ensuring that maintenance and operation can be attended to at all hours.

Windmills are not only used for grinding grain or pressing materials but are increasingly employed in drainage and water management, particularly in the Netherlands and England, where extensive land reclamation projects depend on them. By 1650, large-scale drainage mills are used to pump water from low-lying farmland, protecting crops from flooding and expanding arable land. These developments mark the windmill as a crucial element of industry and agriculture, allowing production to continue even in regions where water power is insufficient or unreliable.

Placement

Windmills require a sufficient source of wind, which can be obtained in steppelands or in places adjacent to salt-water seas that have been denuded of trees. Hexes that contain single hills, that are as developed as type-3 or better hexes, may also serve. Thus, although a type-6 hex can theoretically support a windmill, location also matters.

Windmills rely on consistent wind patterns to function effectively, making them best suited to open landscapes where wind is unimpeded. Steppes and coastal regions, where tree cover is sparse and winds move freely, provide ideal conditions. The absence of natural barriers allows the mill to capture stronger and steadier airflow, ensuring continuous operation. In contrast, densely forested or mountainous areas present challenges, as turbulent winds and obstructions reduce efficiency.

For a windmill to be viable, not only must the hex allow for its construction, but the surrounding terrain must also be considered. Lowland plains with uninterrupted winds, rolling hills that provide elevation and areas where human development has cleared land for agriculture all enhance a windmill's potential. A type-3 or better hex with suitable wind exposure is more likely to support a productive mill, while a type-6 hex may technically allow for one but may lack the reliable airflow necessary for consistent use.

Millers and builders take such factors into account when selecting sites. In flatter regions, taller windmills are constructed to capture higher-altitude winds, while in hilly terrain, mills are positioned at natural wind corridors or on slopes where wind channels effectively. The orientation of the mill is adjusted based on seasonal wind patterns, with some requiring manual rotation of the cap and sails to optimise efficiency. While windmills provide a valuable alternative to water mills, their success depends not only on the classification of a hex but also on the natural geography and prevailing wind conditions that determine their viability.

See also,
Hammer (symbol)
The Adventure