Tide Mill Institute

The Development of the Water Mill

This section includes information on

Undershot Wheels

Horizontal Wheels

Overshot Wheels

Pitch-Back Wheels

Breast Shot Wheels

Flutter Wheels


There are many wheel configurations, vane/blade shapes and water-flow patterns.  Undershot wheels and horizontal wheels were the most common choices for tide mills. Since the height of the impoundment area was the height of high tide, the head of water was probably not high enough to power an overshot wheel.  Also see separate section on horizontal wheels.


Probably the most important of the early engines which utilized water power was the vertical waterwheel. Its two basic forms are the undershot and the overshot. The undershot vertical wheel rotated in the vertical plane and had a horizontal axis. It normally had flat radial blades attached to its periphery and derived its motion from the impact of water flowing under the wheel and against these blades. While capable of working on any convenient stream without mill races (narrow artificial water channels, it worked most effectively in a race and with a stable volume of water running at a fairly high velocity. [Stronger than a Hundred Men: A History of the Vertical Water Wheel by Terry S. Reynolds Baltimore: The Johns Hopkins University Press, 1983.]

Undershot Wheel

Illustration of undershot wheel published in The Tide Mill Woodbridge by M.A. Weaver. Friends of Woodbridge Tide Mill, 1985.

 Larkin: The Undershot Wheel worked in a running stream and could turn in shallow water. It was often built by the first settlers since it was relatively simple to set up … They were common in the early days when a dam could be built to compensate for dry periods … . [Mill: The History and Future of Naturally Powered Buildings by David Larkin. New York, 2000.]

Horizontal Wheel

Tide mills often used horizontal wheels, at first without a housing and later inside cylinders called tubs.

Illustration from Scientifica American 1984


The Tub Wheel could only work where the water flowed regularly throughout the year, and needed at least an eight-foot fall. The tub wheel was horizontal and was described as acted upon by percussion of water. The shaft is vertical, running the stone of top of it, and serves as a spindle. The water is shot on the upper side of the wheel in the direction of a tangent fitted with blades. It revolves in a sturdy tub, projecting far enough above the wheel to prevent the water from shooting over it, and whirls above it until it strikes the buckets. . [Mill: The History and Future of Naturally Powered Buildings by David Larkin. New York, 2000.]

Overshot Wheel


The overshot vertical wheel was a much more efficient device. Water was fed at the op of the overshot wheel into “buckets” or containers built into the wheel’s circumference, and the weight of the impounded water, rather than its impact, turned the wheel. Each “bucket” discharged its water into the tail race at the lower portion of its revolution and ascended empty to repeat the process. The overshot wheel was usually more expensive than the undershot, since a dam and an elevated head race were normally required to build up a large fall of water and to lead the water to the wheel’s summit. It was suitable mainly to low water volumes and moderately high falls.

It is likely that the [emergence of undershot and overshot wheels] was at least partially influenced by several more primitive devices which tap the power of falling water – the water lever, the noria, and the primitive horizontal watermill. [Stronger than a Hundred Men: A History of the Vertical Water Wheel by Terry S. Reynolds Baltimore: The Johns Hopkins University Press, 1983.]

Illustration from Mill: The History and Future of Naturally Powered Buildingsby David Larkin. New York, 2000.


The Overshot Wheel required a dam above it so that the weight of water falling on it would make it turn. After one-third of a revolution, the water was spilled from the wheel. The water first striking the wheel gave it momentum, but the weight of the water in its buckets kept it turning. [Mill: The History and Future of Naturally Powered Buildings by David Larkin. New York, 2000.]

Pitch-Back Wheel

Illustration of pitch-back wheel from Syson.


The difference between the pitch-back and the overshot wheels is that the trough stops shorter here and pours the water onto the wheel before the top of the wheel, or ‘on the near side’ as the millwrights used to say. The result therefore is that the wheel revolves in the opposite direction from the overshot, i.e. towards the flume or head-race. The buckets face in the opposite direction and the water therefore falls off at the same side as that on which it was receved. [British Water-Mills by Leslie Syson. London, 1965]

Breast Wheel

Larkin: The Breast Wheel, like the undershot wheel, turned in the opposite direction to the oversho wheel and received water above its center shaft at the nearest point of the water supply, and revolved easily because it was less loaded with water. . [Mill: The History and Future of Naturally Powered Buildings by David Larkin. New York, 2000.] at on which it was receved. [British Water-Mills by Leslie Syson. London, 1965]

Flutter Wheel

Flutter illustration from Oliver Evans’ plan for an up-and-down sawmill. Scanned from Mill: The History and Future of Naturally Powered Buildings by David Larkin. New York, 2000.

The Flutter Wheel was used when there was a large supply of water. It was small, low and wide—about three feet in diameter and up to eight feet wide. It got its attractive name from the sound it made. As the wheel went around, the blades cut through the entering water, making a noise like the fluttering wings of a bird. It was used almost entirely to power early sawmills. . [Mill: The History and Future of Naturally Powered Buildings by David Larkin. New York, 2000.]


Illustration from Wikipedia

The Turbine with its curved blades, eventually replaced the waterwheel [in the mid-nineteenth century]. … Roy S. Hubbs pointed out that older undershot waterwheels presented a flat blade for the incoming water to impact, allowing half of the velocity to pass through unchecked. The Poncelet design [and the later resulting turbine] presented a curved blade with its lip angled tangentially to the incoming water … Benoit Fourneyron turned the wheel on its side and dropped the water into its center, allowing the water to flow simultaneously out of all the passages between the blades. … Since the turbine used all the openings between its blades simultaneously, it could be made much smaller. It turned much faster than the larger wheels. . [Mill: The History and Future of Naturally Powered Buildings by David Larkin. New York, 2000.]


back to Reynolds for the historyof the water wheel:

Operating on the seesaw principle, the water lever utilized the power of falling water, but without the continuous rotary motion of water wheels. One end of a pivoted beam was equipped with a spoon-shaped bucket. On the other end was a hammerlike counterweight used for pounding or crushing. Water was directed into the bucket from a falling stream; the bucket filled, overweighed the hammer, and lifted it. The ascent of the bucket caused the water to spill; the hammer than overbalanced the bucket and fell. The cycle was then repeated to produce a steady pounding action.

The noria used for raising water, was form of undershot water wheel, but it activated no machinery (such as gears or millstones) beyond itself. It was simply a large vertically situated wheel, sometimes as much at 50-80 feet in diameter, equipped with radial blades which rotated the apparatus as they were impacted by the flowing water in which the lower portion of the wheel was immersed. Buckets of wood, bamboo, or pottery were attached to the rim of the wheel. As the device rotated, they were filed with water at the bottom of the wheel; the water was carried upwards in the buckets and emptied near the top of the wheel into a trough. The buckets were the returned empty to the bottom of the wheel to repeat the process

Based on the surviving evidence, it would appear that the vertical undershot watermill, the horizontal watermill, and the noria appeared almost simultaneously in the Mediterranean world in the first century B.C.
and that at approximately the same time some form of water-powered prime mover was developed in China.

By the close of the Middle Ages watermills were in use on streams of every type. They dammed up the rivers of medieval man; they were on the banks of his brooks and creeks, in the middle of his rivers, under his bridges, and along his coastlines. They impeded navigation and created streams (in the form of mill races and power canals) and lakes (in the form of storage reservoirs behind waterpower dams) where none had existed before.

Through all of antiquity and on into the early Middle Ages almost the only work to which the force of falling water was applied was grinding wheat. This was always to be one of its more important functions. But by the tenth century, European technicians had begun to adapt the vertical water wheel to other tasks. By the sixteenth century, in addition to flour mills, there were hydropowered mills for smelting, forging, sharpening , rolling slitting, polishing, grinding, , and shaping metals. Water wheels were available for hoisting materials and for crushing ores. There were mills for making beer, olive oil, poppy oil, mustard, coins, and wire. Water wheels were used in the preparation of pigment, paper, hemp, and tanning bark, and for fulling, sawing wood, boring pipes, and ventilating mines.

[In North America] the resort to water power usually came quickly after settlement [in colonial America]. The first permanent English settlement in North America was at Jamestown, Virginia, in 1607. Early in that settlement’s history the Virginia Company instructed its governor to build watermills on every plantation. By 1694 Virginia had five watermills. Maryland had a watermill in 1634, the very year it was first settled, and Swedish authorities responsible for settlements on the Delaware in the1640s made the erection of watermills one of their first concerns. The colony of Massachusetts, first settled in 1620, had a watermill at Dorchester by 1633, and mills at Roxbury, Lynn, and Watertown by 1635. These were all flour mills. But according to one authority, the Piscataqua River at South Windham, Maine, was dammed for a sawmill as early as 1623. In 1646, on the Saugus River, Massachusetts built an iron mill, complete with water-activated trip-hammers, blast furnace, bellows, rollers, and slitters. By 1700 there were few New England villages without a watermill.