Disconnectable Mooring Buoy Layout for Faster Offshore Hook-Up
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Solution Overview
Problem
The existing disconnectable mooring systems for offshore semi-submersible floating structures, such as floating offshore wind turbines, are cumbersome and costly due to the need for multiple mooring lines and power cables, which require lengthy and risky operations to connect and disconnect, especially in deep water or congested areas, and current turret buoy designs are impractical for semi-submersibles due to their asymmetric structure and potential for twisting or requiring swivels.
Innovation Solution
A disconnectable mooring system with a buoy that connects and disconnects from the structure, featuring mooring lines with buoy chains that support the mooring chains when disconnected, allowing for a spread mooring configuration with reduced environmental loads on the buoy, and a swivel-less design that enables efficient and controlled connection and disconnection of mooring lines and power cables from shallow water depths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple mooring lines and power cables are used to secure the floating structure, then the structure can maintain stability and position, but the connection and disconnection operations become lengthy, complex, and risky
Solution Approach 1:
The mooring system is divided into separate functional modules: a buoyancy module, a mooring line module, and a connection module. This segmentation allows each component to be optimized independently and facilitates quicker assembly and disconnection operations while maintaining overall system stability.
Solution Approach 2:
A buoyant intermediary device is introduced between the floating structure and the seabed anchors. This buoy acts as a mediator that simplifies the connection process by providing a stable, floating interface that can be quickly connected and disconnected, reducing operational time and risk while maintaining mooring reliability.
2Strength
If traditional turret buoy designs are used with asymmetric structure, then the buoy can support mooring lines, but the structure may twist or require swivels which complicates the system
Solution Approach 1:
The buoyant structure employs a symmetric design rather than the traditional asymmetric turret buoy configuration. This symmetry eliminates twisting issues and removes the need for complex swivel mechanisms, thereby reducing system complexity while maintaining the ability to support multiple mooring lines effectively.
Solution Approach 2:
Instead of using an asymmetric structure that requires swivels to handle rotational forces, the invention inverts the approach by using a symmetric buoy design that naturally resists twisting. This inversion of the traditional design paradigm simplifies the overall system while maintaining structural integrity and mooring support capabilities.
3Stability of the object's composition
If mooring lines are connected individually to each corner of the structure, then the structure maintains fixed heading and stability, but the hook-up process becomes lengthy and difficult especially in deep water or congested areas
Solution Approach 1:
Multiple mooring line connections are merged into a single integrated buoyant structure. Instead of connecting each mooring line individually to different corners of the floating structure, all mooring lines converge at the buoy, which simplifies the hook-up process by reducing the number of separate connection operations required while maintaining the stability and fixed heading characteristics of the original spread mooring configuration.
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 reduces the complexity and cost of mooring operations by allowing rapid and safe connection and disconnection of mooring lines and power cables, minimizing vessel maneuvering and risk, while maintaining structural stability and electrical continuity, even in harsh environments.
Implementation Method 1
the buoy chain supports the mooring chain, preventing the mooring connector contacting the seabed
Data Source
AI summary
A disconnectable mooring system for offshore semi-submersible floating structures. A disconnectable buoy has a number of mooring lines which include a buoy chain between the mooring chain and the buoy. The mooring chain and the buoy chain are connected via a three way mooring connector, with the third connection configured to pull the mooring connector to a mooring point on the structure. In a first configuration the buoy is disconnected and supports the mooring chains for recovery at shallow depths to be pulled in. In a second configuration, the mooring lines are pulled in via the mooring connectors thereby providing a spread mooring to the structure with the buoy chain left as a catenary between the buoy and mooring point.