COMPACT hydraulic cylinders designed for use in places where normal cylinders cannot fit have proved their worth in one of the largest lifting operations ever undertaken in the Northern Territory.
The RCS-1002 Flat Jac series cylinders from Enerpac - which can each deliver 90 tonnes of lift from a starting height of just 141mm - were used by Specialised Labour and Engineering to hoist a Port of Darwin container crane being modified then relocated by ship from Fort Hill Wharf to East Arm Wharf.
The 70-tonne capacity IHI container crane eventually weighed more than 850 tonnes after modifications were completed for the Northern Territory Government to extend it by about 5.5 metres across its wheel gauge to bring it in line with current world standards in an $3.5 million contract covering the total upgrade and relocation.
The meticulous work of safely and precisely completing modifications while the crane was still in operation was conducted during periods of shipping inactivity right up until the time when the crane was decommissioned for transport aboard the heavy lift vessel, The Happy Buccaneer.
Enerpac's single-acting, spring-return Flat Jac cylinders were used in two groups of four to successively lift each side of the crane structure so its original legs could be removed then repositioned as the crane was rebuilt to the wider track profile.
First the seaward side of the crane, then the landward side, was lifted in a safety-first operation during which two groups of four cylinders were employed in a two-stage lift.
Spacers fabricated by SLE being used to support the structure as the cylinders, with a maximum stroke of 57mm, were extended twice to reach the required height.
Manifolds designed by SLE controlled the lift, which was completed as part of the initial stage of the work on behalf of the Northern Territory's Department of Infrastructure, Planning and Environment.
This initial stage involved strengthening of the main load bearing portals; fitment of new portal sections to accept bogie assemblies in their new positions; and the construction and installation of portal sections to fill in the gaps left by the legs.
In addition, four lifting assemblies, rated to 250 tonnes each, were manufactured and fitted to the crane for the relocation after transport by "the Happy Buccaneer," which was equipped with two 550-tonne cranes.
Successful completion was due to careful planning of all works undertaken, from the hydraulic lift through to development and implementation of specialised welding procedures, a rigorous safety management plan, careful adherence to the project schedule and timely sourcing of compatible steels and other materials from throughout Australia and overseas.