|Alatas Service||Field Service, Engineering, Parts Supply|
|Location||Mobile Shipyard, Alabama, USA|
|Crane Type||Dry Dock Wingwall, Portal|
Crane Rope Luffing
|Crane Model||CBW-8800 (Diesel)|
Alatas Americas was contracted for a portal crane slew bearing change out in Mobile, Alabama. On top of performing the change out itself, we provided a comprehensive work package that included engineering, supply of equipment and parts, mobilisation of labour and load testing.
The slew bearing for an Amclyde CBW-8800 portal crane attached to a dry dock wingwall at the Mobile Shipyard was experiencing excessive axial play beyond the manufacturer’s tolerances.
Mobile Shipyard contacted Alatas Americas for a quote on price and availability for a replacement slew bearing. Alatas Parts Supply team provided the best price and delivery time, beating the other companies competing for the client’s business.
The client then asked Alatas Americas to provide a proposal for the change out to the slew bearing itself. Our expert engineers submitted a proposal to jack the crane up and using a sliding skid to carry out the work. After assessing our detailed plans, the customer awarded the job in addition to the parts supply.
Preparation for installation
The work began with Alatas Americas mobilising a mechanical engineer to the site. Here they took the crane’s specific dimensions of the Amclyde CBW-8800 for the complete engineering and integration of the jacking system. The mechanical engineer handed the specifications to our engineering team in Houston, Texas, who engineered a jacking system to mount to the crane pedestal and jack the superstructure of the crane up.
Our engineers planned the system using an ENERPAC jacking console with QTY 4 – 75T solid double-acting cylinders. Once the Houston team finalised the methodology, we procured all materials required for the jacking frame, bearing slide-out, and jacking system.
With all materials gathered, Alatas Americas fabricated all aspects of the jacking system in-house. Then, they delivered all components to the Mobile shipyard in Alabama three weeks before Alatas Parts Supply team delivered the new slew bearing. This timing meant everything was in sync, ready for installation.
Building the jacking system
We sent a senior service technician to the shipyard for the jacking system installation. Working with the welders and helpers supplied by the customer, our service technician installed and welded the jacking frame system to the crane. Once the team had completed all welding, a test was performed on the jacking frame and an MPI inspection was carried out on all critical weld points.
Installing the slew bearing for the portal crane
Alatas Parts Supply delivered the slew bearing on time to the customer’s site, and our senior service technician led work on the jacking activities. Alatas Americas and customer supplied mechanics boomed the crane down to 14 degrees and applied a 14k lbs clump weight to the hook as a counterweight to centre the crane CG for jacking operations.
The jacking operations allowed the loosening of the slew bolts, and once the crane was lifted 25mm above the pedestal, all slew bolts were removed by the team. Alatas continued the jacking operations until the crane was 300mm above the pedestal to install the slide-out frame. Then the team lowered the old slew bearing onto the slide-out frame. The old slew bearing was slid out, and the new slew bearing was slid into place, ensuring the holes lined up.
Alatas Americas slowly lowered the crane onto the new slew bearing and installed all new slew bearing bolts and torqued down in an engineered sequence. Then they removed the jacking system frame and function tested the crane.
Next, the new slew bearing was pumped with the appropriate grease and slewed completely in each direction six times while stopping each rotation for grease pumping.
To complete the work, our team and customer load tested the crane and certified it for use. We performed all work on time and on budget, all performed safely without incident.
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