Here are Don and David fitting the new sluice gate. Don has designed a rack and pinion system to control the water flow. He has followed traditional practice carving the engineer's name (that's Don) and the year into the front panel. The water is held back by the stop boards further back since the dagger-boards for the new sluice gate haven't been installed yet. Even with low flow rates the fine sheet of water is evident as it flows over the tray it resembles a sheet of black plastic.
Bedfordshire drainage board finished dredging the river last week and we were keen to try the new sluice tray. Shifting thirty years of accumulated silt is challenging. As we lifted the stop boards we were rewarded by a beautiful clean flat sheet of water flowing over the new sluice tray.
The water is running properly again after a very long time resting. We continue to excavate the tail race by hand and hope to render the waterwheel "dry" ie running with clearance below the buckets rather than flooded which loses efficiency.
The new sluice is made of of Accoya. The tray curves very slightly to direct water into the waterwheel buckets.
Accoya is a remarkably stable material used extensively in the waterways of the Netherlands. It is is guaranteed to last 25 years submersed in water and 75 years as a cladding material.
Finding the right bolts to hold the new buckets onto the waterwheel has taken some time and a sample or two along the way. Here we have a stainless steel bolt combined with a tapered SG-iron washer that matches the geometry of the grey cast iron waterwheel flanges the washer ensures that the fixings operate properly.
We've closed the mill gates to stop the flow of water over the waterwheel. Now that the wheel has dried out, we can remove the rusting buckets and start to renovate the wheel, ready for new buckets to be installed. Once the buckets have been removed, we'll be able to inspect the wall behind and remove whatever had stopped the wheel from turning. When the frame has been renovated, we'll install new buckets and then look at renovating the mill gates and mill tray.