Slew Bearing Replacement

ALATAS’ SERVICEFIELD SERVICE
LOCATION  ASIA / MALAYSIA / OFFSHORE
EQUIPMENT  SHIP CRANES / OFFSHORE CRANES
BRAND / MODELSEA CRANE K55-90

INTRO:

ALATAS Singapore has recently been tasked with replacing the slew bearing on our client’s SEA CRANE pedestal crane offshore in Malaysia. A comprehensive plan had to be devised and built, and the project had to be delivered as a fully turn-key solution.

This slew bearing replacement is accomplished using a jacking system, and as such, Alatas offered a modular design solution where over 75% of components were interchangeable between different crane configurations.

BACKGROUND:

Every crane is subject to a 6-year comprehensive overhaul as part of the maintenance strategy. Because the slew bearing on this crane has never been replaced before, the customer decided to replace it with a new one.

ALATAS’ SOLUTION:

Alatas Singapore’s response was to offer a full turnkey solution, leveraging multi-office working to guarantee that our client received high-quality and efficient service. Alatas Singapore’s engineering team completed the initial site survey of the crane to gather crucial information to allow the design process to be completed. Alatas UK’s design team developed the jacking system solution. Alatas Singapore fabricated the jacking system’s structural components. Alatas Singapore supplied the specialist jacking console and hydraulic cylinders, and the engineering team produced the detailed work packs and RAMS. Alatas Singapore engineers and field service technicians completed the full onshore trials and offshore delivery of the project.

JOB SCOPE:

Jacking Frame Design

  • Review crane data and select the most suitable jacking method
  • 3D Model Crane
  • Design Jacking Frame around the design and dimensions of the crane Pedestal and Chassis
  • Check Stress Valves using predicted loads
  • Design a skidding frame to allow efficient replacement of slew bearing

Jacking Frame Fabrication

  • Establish ITP and Quality Plans
  • Fabricate Jacking Frame
  • Supply all Fixings
  • NDT and Testing
  • Provision of Manufacturing Record Book and Certification Pack

Jacking Frame Construction

  • Manage construction of Access and Load-Bearing Scaffolding
  • Lift Plan and Rigging for lifting Jacking Frame Components into position
  • Assemble and Test the Jacking System
  • Pre- and Post-NDT of Welds

Slew Bearing Changeout

  • Disconnect and Remove the Slip Ring
  • Remove both Slew Motors, Brake Packs, and Gearboxes
  • Remove Slew Bolts
  • Controlled Trial Lift to determine the center of Gravity
  • Jack-Up Crane
  • Check Pedestal Flatness using a Laser and provide a condition report
  • Remove the Old Slew Bearing and Install a New Slew Bearing
  • Jack Crane Back Down
  • Install and Tension Inner and Outer Slew Bolts (Rotabolts)
  • Re-Connect Slip Ring

Commissioning

  • Full Visual Inspection
  • Backlash, Rocking Motion, and Teeth Flank Contact Check completed
  • Function Test
  • Load Test using water bags and load cell
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