Mill construction details
I have done some improvements on the water wheel detailing, based on discussions with Andy Selfe, who has been involved in watermill restoration.
This mostly has to do with bracing where the arms of the waterwheel intersect. (refer to the article below)
This 3D computer reconstruction shows the mill machinery. Water flowing along the Launder falls through a hole at the top of the wheel. The wheel turns an axle, which drives the toothed Pit Wheel. The Pit wheel drives the Runner (top) stone via the Lantern gear.
In this image, only the mill machinery is shown. The stones are semi - transparent to show the quant, a cross- shaped piece of steel, attached to the vertical shaft and set into the bottom of the runner stone. The cone in the top of the runner stone fits into a hole, into which grain falls to reach the grinding serfaces between the stones. The lower stone, or bed stone, has a much smaller hole, allowing only the shaft to pass through. This is caulked with canvas to prevent grain from falling through. The only way out is between the stones, where the ground meal moves outward by centrifugal force and the action of the grooves cut into the grinding surfaces of the stones. A sweep attached to the Runner stone moves the ground meal to the outlet spout of the Tun.(not shown)..
This image is an 'explodametric' version of the one above.The relationship of the various components can be seen. Additions to the previous drawings (article below) are the bracing pieces for the clasp arms of the water wheel, the rebates wher the Clasp arms cross and an angle at the top of the water buckets to help 'cut' the water.
Els River Mill
I have used Dr John Clifford's study of the mill included in ‘Glencairn Gleanings’, published by the Simon’s Town Historical Society 2003, Ute Seeman’s report prepared for the Simon’s Town Historical Society in 1998, James Walton's book ‘Watermills, windmills and horse mills of South Africa' (1974), my own observations and measurements and various other snippets found in the Simon’s Town Museum files to draw a resolved set of plans of how the Glencairn mill could have been. Where information is completely lacking, I used my own experience as an architect to design it.
For further accuracy of the model it would be necessary to clear the vegetation and excavate collapsed material to establish levels, find old remains or artifacts and materials used. This work should obviously be done professionally. The mill is situated on land now owned by the Navy (sportsfields), which was previously ‘Welcome Farm’ (now the suburb Welcome Glen) and is near the drift in the dirt road leading to the stables.
PLAN:Two internal dimensions were taken and the building assumed to be square for convenience. The ‘annex’ is measured only in width. Ute Seeman’s plan shows an out of square building, which is probably more likely. (Accurate measurements are impossible with dense alien vegetation and rampant brambles). Dashed lines represent steps shown on US’s plan. I could not find much trace of these, nor purpose. They may have led to an opening into the annex (an apparently later addition), or enclosed a rock jutting out of the natural embankment against which the mill is built, or just be a neatly-fallen down piece of masonry. (The way the masonry has collapsed may suggest an opening in the position shown). Timber stairs would be much easier to construct than stone stairs as well as being much more space-effective. These could have been situated anywhere. The difference in levels between the rear of the building and the mill floor would make it very convenient to supply the building from the rear at the level of the grain hopper. The way the masonry has collapsed could suggest a doorway in the position indicated. The window to the right of the wheel, overlooking the tail race seems to be a given and US’s side elevation drawing even seems to show some bits of wood left from the frame in 1998. The front door I have positioned centrally on the gable. This could have been situated more to the left to improve light and easy access to the working area near the mill controls. Dash-dot lines represent the main structural roof elements. These have been set out from centred over the millstones as a double truss would have probably been used to support a block for lifting the stones. Diagonal lines represent the short hip rafters forming the ‘Wolwehoek’ gables. The front gable could have been a full gable as seen at ‘La Cotte' water mill, Fransch Hoek. Welcome Farm seems to have been quite big on gables – Welcome Cottage has five of them. Roof covering was obviously thatch. I don’t know where Simon’s Town got her thatch from in 1820 but it must have been readily available. Local Restio reed would probably also work quite well. The mill race position is quite clear near to the mill and from this the flume position and therefore the wheel position can be deduced. ELEVATION: The position of the axle slot and a single ‘Batavian’ brick (or slate tile), showing the springing point of the arch can be seen. There is also a clear groove in the plaster formed by some protuberance from the wheel, probably the bolt heads securing the ‘floats’ in position. From these, the approximate diameter of the wheel and axis can be deduced. The flume may have been higher than shown, depending on the lining used for the mill race. The height of the roof is determined mainly by the height requirement of the building (in section) and the highest surviving masonry. The roof orientation is generally determined by having the rafters spanning the shortest span. I find it unlikely that the entire roof would have been made higher just to accommodate a window above the flume (apparently a common position for the control of the flume hatch and therefore the mill machinery), unless it had it’s own gable (also unlikely). The idea of a window directly above the hopper, from where the miller would have to somehow lean out through a one meter thick wall after scrambling up a ladder in order to turn off his machine, seems a bit illogical. It seems more likely to me that it was controlled from the other window to the right of the wheel. There is a straight line and some holes in the remaining plaster that I have extrapolated to suggest a position for the control hatch and a lever system. I assume the window would have had a shutter opening away from the wheel with a latch on the wall to hold it back.
Assuming there is another window above the front door, there would be plenty of light and cross-ventilation to the mill, especially near the ‘control’ window. All the mill controls could be convenient to this area i.e. the hatch control lever, the bridge-tree lighter screw (clearance between the millstones), the crook-string twist-peg (the riempie controlling the shoe angle and therefore the grain flow rate) and whatever the controls were for the meal dressing machinery occupying the floor next to the milling machinery (this is referred to in an auction notice for Welcome Farm from 1842, which describes it as “…a substantial Flour Mill with dressing machine and Bakery, erected on the banks of he Else River”). The bakery has apparently disappeared and it is unlikely to have had anything to do with the annex due to the danger of explosion associated with fire and flour milling.
SECTION:From the position of the axle tree supports, the required levels can be determined for the tail race, pit-wheel pit and approximate floor level. It is also evident from the scale of the building that part (or all) of the building probably had a second storey platform. Feeding the grain sacks in through the upstairs ‘back’ door and then sacks of dressed flour out through the front would have made an efficient system that required no lifting of heavy meal sacks.
The ‘annex’ could have been added as millers' accommodation, extra storage space or social space for people hanging around waiting for their flour. The annex is very low (if the main roof is in the right place) and it’s walls much thinner than the mill, which would suggest that it was not a very important structure, most likely for storage I think. The floor level of the annex may well have been lower, if it had a floor, but this can only be established by digging some holes to fix proper levels.
MACHINERY:The water wheel is a clasp-arm type, which had apparently replaced compass arm wheels by 1820. The shrouds are 230mm deep with 32 floats of 250mm long (numbers derived from JC’s notes) and chose an arbitrary angle for the buckets. Measured with AutoCad I get a potential stationary load of 100 litres and I suppose maybe 80 litres when spinning. See Dr John Clifford's notes for more information regarding power to the machine. For the pit-wheel, I have taken a diameter of 1.2 metres, based on a picture from James Walton’s book showing a small–looking man standing next to an assembled pit wheel and lantern (p75). It has 53 teeth to put it out of sync with the 8 lantern rungs to ensure even wear.
The millstones have a diameter of 900mm and start out 200mm thick. The depth of the lantern will allow them to wear down to about 75mm before replacement. (this was apparently usual). Millstones may have been smaller or thicker than this.
I have assumed sizes and positions for the damsel, feed shoe and hopper, only making sure that they would work together as a unit. There must be a lot of possible variations here.An important feature is the alarm bell, which drops against the knocker when the weight of grain in the hopper no longer presses against the hinged metal plate inside the hopper. This would alert the miller to either shut down the machine, yell at his apprentice to feed more grain, (or go upstairs himself to do it). Apparently, letting the grain feed run out could result in rapid damage to the stones, or at worst, cause sparks leading to an explosion.
The dressing machine consists of an agitated, inclined sieve of varying grades, fed from the outlet of the stones vat and emptying into the meal kist, from where it is bagged to varying grades. The agitating rod was driven off the mill machine somehow (cog or cam) and could presumably be disengaged. (this is not shown in the model)
CONCLUSION: There doesn’t seem to be much more to seen from the visible ruins, but I am sure that a properly supervised excavation could yield some interesting information which may verify or inform my, (and/or Ute Seeman’s and John Clifford's) assumptions and conclusions and at least make an interesting story. I like the idea of using the site as a supervised student ‘dig’. An interesting challenge would be excavating the tail race as the river seems to have silted up quite a bit since last century (and even since Ute Seeman photographed it in 1998).