An offshore crane is defined as a pedestal-mounted elevating and rotating lifting device used to transfer materials and personnel to and from marine vessels, barges and structures. According to API Spec 2C, these are some of the crane terminology:
- Auxiliary (whip line or fast line): The secondary rope system,capable of lifting a lower capacity than the main block
- Boom: connected to the upper structure and supports the hoist
- Boom hoist: raises and lowers the boom
- Boom suspension: the collection of wire ropes, sheaves, shafts blocks and other rigging components used to support the boom
- Cab: where the operator maneuvers the crane’s controls
- Gantry: a frame to which the boom support ropes are reeved
- Kingpost: connects to the platform and is the centerline of rotation for the upper structure
- Pedestal: the substructure the upper structure is mounted on
- Revolving superstructure: the rotating frame structure and the operating machinery mounted
*Definitions provided by API 2CA
With the growing demand in offshore oil and gas exploration, the need for highly efficient offshore cranes has surged. Offshore cranes play a critical role in heavy-duty operations such as supply, repair, maintenance, assembly, and decommissioning of oil and gas extraction systems. These cranes offer exceptional lifting capabilities, with some able to lift up to 10,000 tonnes, making them essential for operations in challenging offshore environments.
Machining of Crane tub
At our company, we specialize in providing precise machining services for offshore cranes, ensuring that they meet the highest standards of accuracy and performance. Our expertise covers both bogie wheel system lifting cranes and bearing system lifting cranes, providing reliable solutions to enhance the functionality of your cranes.
Precision Machining Services for Offshore Cranes:
- Crane Tub Machining
Our precision machining process ensures that the crane tub operates seamlessly, allowing smooth crane rotation. The tub’s movement, whether driven by bogie wheels or bearings, is essential for the crane’s overall performance. - Bull Gear Seating Face Machining
We achieve exceptional accuracy in machining the bull gear seating faces. Our team has successfully machined 72 evenly spaced pads on a 28-meter diameter pitch center, achieving less than 3mm elevation height difference. This precision is critical for smooth crane operation. - Surface Milling for Roller Path
We specialize in surface milling of large-diameter roller paths, such as a ⌀26m roller and hook roller path with a 500mm width. Our work ensures flatness runout of only 0.8mm, meeting the strictest industry standards. Our clients also leverage this setup for overhead pad installations. - Bolt Hole Machining for Bull Gear Installation
We excel in machining bolt holes for bull gear installations, including 144 x dia 62mm fit bolt holes, using portable precision machines such as the BB5000 Climax. This ensures perfect alignment for efficient gear installation on deck. - King Post Bolt Hole Drilling
Our match drilling service includes drilling 24 x dia 74mm king post bolt holes using Mirage drilling machines. This ensures accuracy in critical areas of crane installation. - Overhead Milling for Crane Deck Foundation
We provide overhead milling services for crane deck foundations, achieving surface flatness runout of less than 0.5mm, meeting the highest precision standards for offshore projects.
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Our extensive experience in FPSO turret machining allows us to transfer valuable domain knowledge to heavy lift crane projects. We have gained insights from working with renowned crane designs such as Huisman, AmClyde, GustoMSC, and Liebherr, enhancing our capabilities across various crane systems.
During new-build projects, critical areas requiring machining include kingpin seating face, bull gear seating face, bogie wheel track, counter support track, and bearing seating face. Our focus on achieving tight GD&T tolerances, such as flatness and parallelism, ensures reliable and long-lasting crane performance.
Innovative Machining Capabilities:
- Camber Profile Milling
Using our customized numeric-controlled circular milling machine with 2 degrees of freedom, we can mill camber profiles on circular flat surfaces of crane pedestals. This ensures precise, efficient, and reliable machining solutions for your crane projects. - In-Situ Machining for Maintenance
For maintenance operations, such as changing out the slew bearing, our low-profile machines allow for in-situ machining in tight spaces. Our equipment requires minimal headspace, making it ideal for operations in restricted areas, such as bearing seating faces.
Our team’s vast experience, combined with state-of-the-art machinery, ensures that we can meet the demanding requirements of offshore crane machining projects. We specialize in delivering precision results, minimizing downtime, and ensuring your equipment operates at its peak performance. With experience in working on a wide variety of crane systems and in-depth knowledge of offshore operations, we are your trusted partner in crane machining solutions.
Let us help you optimize your offshore crane performance with our expert machining services.
Camber profile on circular flat surface on crane pedestal is also achievable using our customised 2 degree of freedom numeric controlled circular milling machine.
As for maintenance process like changing out of slew bearing, insitu machining on the bearing seating face can be carried out in tight overhead space using our low profile machineries which required very less head space for operation.
