by Trevor Bevins, Local Democracy Reporting Service.
Emergency repairs to the iconic Cobb at Lyme Regis could begin next week.
The structure, probably the most famous man-made feature in Dorset, has been seriously holed below the waterline on the seaward side.
The holes are so large that there is a fear that stonework above could collapse unless immediately repaired.
Listed Building consent is being request to carry out the work which will mean pumping concrete into the void which has been created by storm waves.
Councillors were told at a recent harbours committee meeting that the cost is likely to be around £350,000.
Dorset Council, which has made the application for the Grade 1 listed structure repairs, says the work will involve a temporary counterbalance scaffold and Haki steps to reach the affected area, filling it with marine concrete at what is known as the Ginshop Turn on the Cobb, an indentation in its structure.
Said an expert report on the damage: “The assessment shows that urgent works are required imminently due to its vulnerable location and focus point for wave energy during winter storms. The size of the void was also of great concern, with a depth of up to 2 metres, a width of up to 7 metres and a height of 0.3 metres, leaving large blocks unsupported deep within the structure and at imminent risk of collapse.”
Said a specialist archaeologist report: “The Cobb is widely considered to be the earliest surviving example of a structure of its type in the country and as such is considered to be of Very High importance,” said the report from specialist archaeologists.
While the works are carried out fishing operations are expected to be able to continue although the Cobb Roadway will be closed to commercial traffic, allowing deliveries for the repairs but limited to vehicles of no more than 7.5tonnes, with heavy boarding and matting placed on the Cobb to prevent further damage.
Due to the location of the holes the repair work can only take place at spring tide lows – limited to four days in early November, but even this cannot be guaranteed because of the weather. Special concrete will be used which pumps at high pressure and sets within two hours.
The scaffolding and steps will be put in place a week before with a weighted counterbalance system to stabilise the scaffolding with the steps lowered from the scaffolding to the base of the wall.
One tonne concrete blocks will be lifted by crane in front of the repair to help reduce the impact of waves once the void is filled.
THE emergency repairs are separate to the next phase of coastal works at Lyme Regis likely to cost around £8.4million to secure the Cobb for years to come.
Dorset Council’s flood and coastal erosion engineering manager Matthew Penny said recently that talks were ongoing between the council and Historic England over the project and, if all goes well, construction is still planned to start this winter, continuing until the spring of 2027.
The harbour defences are thought to have been built in the 13th century and have been extensively repaired and rebuilt over the centuries.
Cobb with marked area showing location of the hole. Image: Google
Cobb hole underneath seaward wall. Dorset Council