Vertical Winch Drum Offshore Crane Footprint Reduction
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Solution Overview
Problem
Offshore lifting cranes face challenges with large, heavy winch drums required for deepwater operations, leading to excessive wear of fibre ropes and impractical installation due to high centre of gravity and footprint, which complicates and costs installation.
Innovation Solution
Integrating the winch drum vertically with the support structure, reducing its footprint and weight, and allowing pre-mounting and testing onshore, with a compact design that lowers the centre of gravity and simplifies installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the winch drum is made large to store several thousand meters of wire rope for deep water operations, then the hoisting capability for deep water is improved, but the footprint and weight of the winch drum increase excessively
Solution Approach 1:
The winch drum is rotated from a horizontal arrangement to a vertical arrangement, changing the spatial dimension in which the winch drum occupies space. This allows the winch drum to store several thousand meters of wire rope while having a reduced horizontal footprint, as the drum extends vertically rather than horizontally.
2Length of moving object
If the winch drum is made large to store several thousand meters of wire rope, then the hoisting capability for deep water is improved, but the weight of the winch drum increases excessively
Solution Approach 1:
By reorienting the winch drum to a vertical position, the patent utilizes the vertical space to accommodate the wire rope storage length, thereby reducing the horizontal footprint and allowing for a lighter overall structure compared to a horizontal arrangement that would require extensive horizontal space.
3Ease of operation
If the winch drum is placed on an upper portion of the crane on a platform extending horizontally away from the crane housing, then the winch drum can be accessed, but the crane develops tail swing and a relatively high centre of gravity
Solution Approach 1:
The winch drum is repositioned from a horizontal platform extension to a vertical arrangement integrated with the crane housing. This vertical integration eliminates the need for horizontal platform extensions, thereby reducing tail swing and lowering the centre of gravity while maintaining operational accessibility through vertical access points.
4Stability of the object's composition
If the winch drum is placed below deck of the vessel to reduce tail swing and centre of gravity, then the crane stability is improved, but the installation becomes significantly more complex and time-consuming
Solution Approach 1:
The winch drum is merged with the crane housing structure, creating an integrated assembly that can be pre-mounted and tested onshore before installation. This integration simplifies the installation process by reducing the number of separate components that need to be installed below deck, while still achieving the stability benefits of a lowered centre of gravity.
5Weight of moving object
If fibre ropes are used instead of steel wire ropes for deep water operations, then the weight of the hoisting member is reduced, but the fibre rope suffers excessive wear leading to unacceptable short lifetime
Solution Approach 1:
The vertical arrangement of the winch drum changes the geometry of the fibre rope spooling pattern, allowing the rope to be wound in a manner that reduces repeated bending cycles and friction heat generation. This dimensional change in the winch drum orientation thereby reduces wear on the fibre rope while maintaining the weight advantages of fibre rope over steel wire rope.
Data Source
AI summary
Described is an offshore lifting crane, as for a vessel or platform, that includes a support structure, a crane boom connected to the support structure, a winch drum rotatable around its longitudinal axis, a winch drum drive means, and an elongated hoisting member. The hoisting member includes a first end connected to the winch drum and a second end connectable to a load. The hoisting member extends over at least a part of the crane boom, and the winch drum is arranged such that its longitudinal axis is substantially vertical.