Retractable Mooring Layout for Shallow-Water Platform Stability
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Solution Overview
Problem
Existing mooring systems face challenges in shallow waters due to reduced catenary effect, requiring long and heavy anchor chains, increased costs, and interference with marine activities, posing safety risks and instability to floating platforms.
Innovation Solution
A flexible retractable mooring system with power generation devices and anchors, utilizing tension in mooring cables and anchor chains for power generation, and incorporating a reset mechanism to maintain tension within a safe range, enhancing stability and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If catenary mooring system is used in shallow waters, then restoring force is provided by weight of sag bend, but the catenary effect is greatly reduced due to limited water depth, resulting in significant decrease in mooring performance
Solution Approach 1:
The patent employs a dynamic mooring system where the mooring cable transitions between catenary and taut states based on platform displacement. The cable can dynamically adjust its configuration, switching from a sagging catenary form when the platform is near equilibrium to a taut form when displaced, thereby maintaining effective restoring force in shallow waters without requiring excessively long anchor chains
Solution Approach 2:
The system changes the physical state and parameters of the mooring cable throughout its length. The upper portion operates in a taut state providing immediate restoring force, while the lower portion near the seabed operates in a catenary state providing damping and energy dissipation. This parameter variation along the cable length optimizes performance for shallow water conditions
2Strength
If extremely long and heavy anchor chains are used to provide sufficient restoring performance, then mooring strength is ensured, but maintenance becomes extremely difficult and budget increases
Solution Approach 1:
The mooring system is segmented into functionally distinct zones: an upper taut section for providing restoring force and a lower catenary section for damping and energy absorption. This segmentation allows each section to be optimized independently, reducing the overall length and weight of anchor chains required while maintaining sufficient mooring strength
Solution Approach 2:
The patent converts the typically harmful impact loads and dynamic forces acting on the mooring system into beneficial energy dissipation through the catenary portion. The sag bend acts as a mechanical damper, converting kinetic energy into potential energy and back, thereby reducing peak loads and extending the service life of the mooring components
3Reliability
If extensive anchor chains are deployed, then sufficient restoring performance is achieved, but huge seabed area is occupied, potentially interfering with other marine activities
Solution Approach 1:
The system utilizes vertical parameter changes in the mooring cable configuration rather than horizontal expansion. By optimizing the vertical distribution of catenary and taut sections, the system achieves sufficient restoring performance with minimal seabed occupation, as the restoring force is generated primarily through vertical cable tension rather than horizontal chain spread
4Force
If taut mooring systems are used, then restoring force is provided by axial cable, but excessive stiffness interferes with wave power generation operations
Solution Approach 1:
Different sections of the mooring cable possess different mechanical qualities. The upper section maintains a taut state with high axial stiffness to provide immediate restoring force, while the lower section adopts a catenary state with high flexibility and damping capacity. This local differentiation of mechanical properties allows the system to simultaneously satisfy both mooring and wave power generation requirements
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
The system stabilizes offshore platforms in shallow waters, effectively harnesses marine energy, prolongs system life, and improves safety by avoiding breakage and interference, while providing additional anchoring support.
Implementation Method 1
the first power generation devices and the second power generation device generate power by making use of tension of the mooring cables and the anchor chains
Data Source
AI summary
A flexible retractable mooring system suitable for medium and shallow water operation, including first power generation devices, a second power generation device, and anchors; where the first power generation devices and the second power generation device are all connected to an offshore platform through mooring cables, and the first power generation devices are further connected to the anchors through anchor chains; the second power generation device is located directly below the offshore platform; and when the mooring system is operating, the mooring cables and the anchor chains are all in a tension state, and the first power generation devices and the second power generation device generate power by making use of tension of the mooring cables.