Gimbal Table Isolates Spar Buoy Motions During Offshore Mating
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Solution Overview
Problem
The high costs and limited availability of large offshore cranes for installing wind turbine generators on floating hulls, such as spar buoys, make existing methods economically unfeasible and risky due to significant relative motions between the spar buoy and installation vessels, especially in larger sea states.
Innovation Solution
A system utilizing a gimbal table to grip the spar buoy from a fork-type vessel, isolating roll and pitch motions, and a support frame assembly with a spring system to absorb angular motions, allowing controlled lowering and attachment of the wind turbine generator, reducing relative motions and loads during installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a large offshore crane is used for installation, then installation capability is achieved, but cost and operational complexity increase significantly
Solution Approach 1:
The patent introduces a gimbal table as an intermediary device between the barge and the spar buoy. The gimbal table includes an outer table attached to the barge and an inner table attached to the spar buoy, with a gimbal mechanism allowing relative motion while maintaining connection. This intermediary system enables the simpler barge to perform installation functions previously requiring complex offshore cranes by mediating the motion differences between the two vessels.
Solution Approach 2:
The installation system is segmented into distinct functional components: the barge (transport vessel), the gimbal table (mating device with outer and inner tables), and the spar buoy (floating structure). This segmentation allows each component to be optimized independently - the barge for transport, the gimbal table for motion isolation and connection, and the spar buoy for its floating function - reducing overall system complexity compared to a single complex crane system.
2Device complexity
If a standard barge/fork-type vessel is used for installation, then cost is reduced, but relative motions between barge and spar buoy increase making mating difficult and dangerous
Solution Approach 1:
The gimbal table serves as a motion-isolating intermediary between the barge and the spar buoy. The gimbal mechanism allows the inner table (attached to the spar buoy) to move relative to the outer table (attached to the barge) in multiple directions while maintaining connection. This isolates the relative motions from the mating interface, preventing dangerous relative movements during connection while still allowing the simpler barge to be used.
Solution Approach 2:
The gimbal table is designed beforehand to accommodate and cushion the relative motions between the barge and spar buoy. By pre-configuring the gimbal mechanism with appropriate clearance and motion ranges, the system absorbs the motion differences before they can cause damage during the mating process, ensuring safe connection even with a simpler barge vessel.
3Ease of operation
If adaptations are made to spar buoy and wind turbine structure for mating, then mating is enabled, but installation cost increases
Solution Approach 1:
The gimbal table acts as a universal intermediary that accommodates different spar buoy and wind turbine configurations without requiring specific adaptations to each. The gimbal mechanism's multi-degree-of-freedom motion capability allows it to bridge various structural configurations, reducing the need for costly custom adaptations to the spar buoy or wind turbine structure while still enabling successful mating.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables cost-effective, safe, and timely installation of wind turbine generators on spar buoys without large cranes, reducing risks and enabling operations in larger sea states by minimizing relative motions and loads during mating.
Implementation Method 1
The support frame assembly is mounted on a spring system to allow the angular relative motions of the spar buoy to be absorbed between the support frame assembly and vessel during mating of the wind turbine generator to the spar buoy
Implementation Method 2
The invention makes use of a gimbal table that grips the spar buoy from the bow or stern of a fork-type vessel and thereby isolates the roll and pitch motions of the vessel from the spar buoy
Data Source
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AI summary
A system and method for mating equipment offshore to a spar buoy secured to a foundation without the use of a crane barge. The system comprises a floating vessel having a pair of forks defining a slot. A gimbal table, defining an opening, is positioned within the slot and connected to the vessel and a locking collar is mounted to the gimbal table. A mating member is attached to the spar buoy. The vessel is maneuvered to bring the spar buoy within the gimbal table opening. With the spar buoy positioned within the gimbal table opening, the locking collar is arranged and designed to releasably attach to the mating member of the spar buoy and restrict relative vertical motion between the spar buoy and the vessel while the gimbal table allows the floating vessel to roll and pitch without driving these motions into the spar buoy.