Over 20 Tonnes of Stop Logs
Camden Lock was built in 1790 as part of the Grand Canal Ringsend Basin construction, and links the Liffey Estuary to the Grand Canal in Dublin. The canal navigation is managed by Waterways Ireland.
As part of Waterways Irelands plans for the refurbishment of Camden Lock a competitive tender competition was advertised for the design, supply and fitting of stop logs for the deep gates of the
lock. In addition to refurbishing the lock chamber the design of the stop logs should allow the chamber to be used as a dry-dock for the inspection of the Jeanie Johnston Museum Tall ship.
Aquatic Control Engineering Ltd (ACE) were awarded the contract by Waterways Ireland in August 2019 to deliver an effective solution to be able to seal off the lock and form a dry dock.
The solution was to use four stoplogs. Installed in to a specially manufactured stainless-steel rebate the entire assembly would be mounted into the existing masonry of the lock following its profile to ensure the required seal.
As principal contractor ACE project managed the design and manufacture of the four stop logs that were manufactured by Jansen Venneboer. The stoplogs once manufactured weighed over 20 tonnes in total.
ACE project managed the supply and installation of the stainless-steel rebates by Marine Specialists with these manufactured to suit both the existing lock structure and the newly fabricated stoplogs. With the assistance of our certified diving partners the underwater concrete base was installed to form a face for the stop logs to sit against and ensure a good seal.
For the installation, a jack-up Barge was brought in as a platform to work from. The first stage was the excavation of all the debris from the site. Once clear the divers were able to commence with the concrete base, using specially designed aggregate to ensure a good seal would be made upon the stop log installation.
With the base complete the team brought in a knuckle boom crane to lift the stainless-steel rebates into place and these were installed by the divers checking alignment and fit for the stoplogs throughout.
With the base and the rebates in place the barge was towed to Dublin Dock to collect the stop logs ready for installation. The four stop logs, each one getting larger, were then lowered into place using the knuckle boom crane. The final stop log which is 12.5m wide was installed making the wall of stop logs a total six metres high.
With everything in place, the lock was drained to ensure the stop log solution was sealed and the leakage rate was well within the agreed tolerances.
ACE managed all of the design and fabrication for the full solution in house which has led to a seamless approach. The project was delivered in time and within budget to the satisfaction of the client, Waterways Ireland.