Two of our UNIC URW-706 Mini Spider Cranes were selected to support the removal and replacement of lock gates during a challenging project for the Canal & River Trust.
Restricted access meant conventional lifting equipment could not reach the lock directly. Instead, both URW-706 cranes were unloaded from road transport, transferred onto pontoons and transported along the canal to the working area.
One crane was positioned at each end of the lock, giving the lifting team the flexibility required to handle the existing gates and install their replacements within the confined site.
A challenging crane configuration
The lock measured approximately 4.7m across and 5m deep, requiring a carefully planned crane setup.
Once positioned, the URW-706 cranes extended their outriggers onto the stonework on either side of the lock, allowing them to straddle the chamber before it was drained. Sleepers and 1m outrigger mats were placed beneath the legs to support the planned configuration and distribute the load.
The URW-706’s flexible outrigger system was particularly valuable in this application, enabling each crane to be configured around the restricted space and uneven working environment.
Removing and replacing the lock gates
The lifting operation included the removal of:
- 800kg balance beams
- A 2,500kg top gate
- A 3,000kg bottom gate measuring approximately 4.65m long
Slings and lifting chains were secured to each component while the existing fixings were removed. The gates were then carefully lifted clear of the lock and lowered onto a pontoon positioned below.
The replacement components were subsequently lifted into the lock and accurately positioned ready for installation.
Controlled lifting in a confined waterside location
Operating alongside water, working from pontoons and positioning two cranes around a confined lock chamber required close coordination between the lift supervisor and crane operators.
To maintain a controlled working area, only one URW-706 was operated at a time. When not in use, the second crane’s boom was lowered to provide additional clearance and minimise interference with the active lifting operation.
Following the successful installation of the replacement gates, both cranes were transferred back onto the pontoons, transported along the canal to the original access point and loaded onto road transport.
Compact dimensions, powerful lifting performance
This project demonstrates the versatility of the UNIC URW-706 Mini Spider Crane in complex infrastructure and waterside applications.
Its combination of lifting capacity, compact dimensions and flexible outrigger positioning allowed the cranes to be transported through a restricted route, configured around the lock chamber and used to complete a series of carefully controlled lifts.
Where limited access, confined working areas or challenging ground conditions rule out conventional lifting equipment, UNIC Mini Spider Cranes provide a compact, adaptable and capable alternative.
