Submerged Blocks

 by George Freeston

When the tunnel was first drained in 1982 for the repairs, which included the short stretches outside the tunnel portals, the derelict side walls, particularly on the West bank, north end, were seen to be in a bad condition. At the Blisworth end, large squared blocks of stone had fallen "topsy-turvy" into the mud. They had once formed the side wall at the tunnel approach. There were also some on the east tow path side. All were duly lifted on to the bank - as pictured.

These displaced stones did not belong to the original canal construction. It is assumed that the original side walls were built up with limestone blocks from local quarries, which soon suffered from the bumping of the boats when mooring or when entering the tunnel — hence the larger blocks were later used to replace the early walling. But where did they originate?

When R. Stephenson constructed his London to Birmingham railway he placed his rails, when passing through cuttings, on large stone sleepers (remember too that the 1800-1805 Blisworth Hill Railway had run on stone blocks). However, Stephenson's blocks soon became unsatisfactory owing to irregular settlement, so they were removed and replaced with wooden sleepers throughout the line. The redundant stone blocks, from this change, were put on the market for around eighteen pence each. It appears that the Grand Junction Canal Co purchased large quantities, for they can be found in many places along the canal length. This explains their presence at the tunnel entrance, allbeit in the water, and at the number 51 bridge hole at Blisworth.

On pointing out their historic worth to the site engineer, he readily offered to make use of them again. But as the side walls were steel piled and topped with a concrete kerb the stone blocks were instead placed in a row along the bank, see photo in which some can be seen, and behind the concrete. It took two hefty miners and a JCB to lift and place the stones. They were used as seats during the re-opening of the tunnel last August. It saddens me however to report that out of the eighteen blocks, only two remain: the others have seemingly been heaved back into the canal — no mean task, for they must have weighed up to 300 pounds each ... and children cannot move such weights.