David: A fascinating morning
CaRT are currently rebuilding Lock 9 on Napton flight and on Sunday they staged an Open Day for anyone to come along and inspect the progress.
The problem was that the towpath side lock wall was gradually toppling inwards, narrowing the lock and threatening to make it impassable.
Demolished the wall
As the pictures show, they have entirely demolished the wall between the gate quoins and are currently laying the foundations for a new wall. The last pour of concrete is due tomorrow and then they will begin bricklaying. Unless cold weather interferes with this, the planned re-opening date of 22nd December will be met, although work will continue for another month or so, finishing off and removing the extensive work site in the neighbouring field.
Unlike most open days it was not possible to descend to the floor of the lock, especially as men were working there (on a Sunday).
Real enthusiast
There was a good view from the fenced perimeter of the lock and several knowledgeable people to explain what was going on, both from the contractor, Kier, and CaRT, including Kier's chief engineer for all their CaRT work south of Coventry, who was a real enthusiast for her job, and a senior CaRT manager who I was pleased to learn is a boat owner.
As is always the case with this sort of work they have little idea of what they will find until they actually start digging, since there are no records of the original construction in the 1770s or of the last major work done, according to a date brick, in 1911. When they exposed the defective wall, they discovered that the 18th century contractors had constructed two parallel walls, tied together only with timber, which of course had rotted, probably causing the problem.
Each built a different way
This is typical of CaRT's experiences in this sort of situation; the Kier engineer told us that she had been doing something similar to two neighbouring locks on the Tardebigge Flight and found that underground each lock had been built in a different way.
This is not so surprising when you reflect that the early canal builders had no precedents to guide them and were essentially making it up as they went along, inventing civil engineering as they did so. There was also the fact that the actual work was carried out by contractors, just like it is now, and each one had his own ideas of how the job could be best done to maximise his profit.
Altogether a fascinating morning and our thanks to all those who turned out on a Sunday to make the visit possible.
David Hymers