Cargo Platform Transfer for Offshore Jack-Up Resupply in Rough Seas
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Solution Overview
Problem
Existing methods for transferring wind turbine generator components between a vessel and an offshore jack-up rig are inefficient, requiring the rig to sail back to port for resupply, and face challenges in transferring loads in adverse weather conditions.
Innovation Solution
A cargo carrying platform with a frame and lifting mechanism is used to secure and transfer wind turbine components, allowing for on-site resupply without sailing back to port and enabling transfers in varying weather conditions through a hull cut-out and stabilizing mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If WTG components are stored on the deck of the jack-up rig in port, then the rig can be replenished with components, but the rig must sail back to port to be replenished which reduces the time available for installation operations
Solution Approach 1:
The system divides the cargo transfer function into separate components: a supply vessel for transporting components, a cargo carrying platform for intermediate storage and transfer, and the jack-up rig for final installation. This segmentation allows the rig to remain at the installation site while components are transferred via the platform, eliminating the need for the rig to sail to port for replenishment.
Solution Approach 2:
The cargo carrying platform acts as an intermediary between the supply vessel and the jack-up rig. It receives components from the supply vessel and transfers them to the rig, enabling the rig to be resupplied without returning to port. The platform includes securing mechanisms and lifting equipment to facilitate this intermediate transfer operation.
2Loss of time
If WTG components are transferred via a supply vessel, then the rig can be resupplied without sailing to port, but the transfer becomes difficult in bad weather conditions
Solution Approach 1:
The system incorporates dynamic positioning and motion compensation capabilities. The cargo carrying platform can be positioned and secured relative to the jack-up rig despite vessel movements. The securing mechanisms include adjustable clamps and restraints that can accommodate relative motion between vessels during weather conditions.
Solution Approach 2:
The system can adapt to changing weather conditions by modifying operational parameters. The cargo platform includes stabilizing mechanisms and the ability to adjust securing forces. The transfer operation can be conducted across a wider range of sea states by adjusting the positioning and securing parameters of the platform and its equipment.
3Productivity
If a detachable deck with rail system is used to lift platforms from the vessel, then WTG components can be transferred offshore, but the vessel requires very calm weather to avoid collision with legs due to heave, roll or sway
Solution Approach 1:
The cargo carrying platform serves as an intermediary that decouples the transfer operation from direct vessel-to-rig contact. It can be secured to the rig and used for component transfer without requiring the supply vessel to maintain precise positioning during the actual transfer, reducing the impact of vessel motion.
Solution Approach 2:
The system segments the transfer operation into distinct phases: loading components onto the platform while the vessel is alongside, securing the platform to the rig, and then transferring components from the platform to the rig. This segmentation allows the vessel to depart after loading, eliminating the need for the vessel to remain stationary during component transfer and reducing exposure to wave-induced motions.
Data Source
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AI summary
A method of supplying a load between a vessel and an offshore jackup (100). The offshore jackup has a hull (102) and a plurality of moveable legs (104) engageable with the seafloor. The offshore jack-up is arranged to move the legs with respect to the hull to position the hull out of the water. The method comprises securing the vessel with respect to the hull of the offshore jack-up when the hull is positioned out of the water and the legs engage the seafloor. A lifting mechanism (406) mounted on the offshore jack-up (100) engages with a cargo carrying platform (228) positioned on the vessel. The platform is lifted with the lifting mechanism between a first position on the vessel and a second position clear of the vessel.