Offshore Floating Structure Mooring and Installation Design
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Solution Overview
Problem
Conventional offshore structures face challenges in installation and decommissioning, including high costs, weather-related delays, and inadequate mooring systems that fail to securely hold mooring lines, especially for large wind turbines in deep water environments.
Innovation Solution
A floating structure design featuring a hull with installation aid structures (IASs) for enhanced stability during installation and decommissioning, a chain engaging system to securely lock mooring lines, and a mooring fixture that pivots to reduce shock loads, allowing for efficient and cost-effective construction, transportation, and removal of offshore wind turbines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the structure is constructed and assembled onshore or near shore and then towed to its offshore destination, then construction cost and complexity are reduced, but the structure cannot be towed through shallow water due to deep draft and requires larger columns/pontoons for stability at shallow draft
Solution Approach 1:
The floating structure is divided into multiple detachable components including columns, pontoons, and a platform assembly that can be constructed separately and assembled offshore. This segmentation allows each component to be optimized independently - columns can be designed for deep draft operation while pontoons provide stability during shallow water assembly and towing operations.
Solution Approach 2:
The structure incorporates adjustable ballast systems and movable components that allow the draft to be dynamically adjusted during different operational phases. During towing, ballast can be adjusted to reduce draft for navigating shallow waters, while during operation the structure achieves its full deep draft configuration for optimal wind turbine support.
2Adaptability or versatility
If the structure is transported to offshore destination and assembled there, then fabrication limitations are overcome, but installation cost increases due to expensive ships and weather-related delays
Solution Approach 1:
The floating structure is divided into multiple detachable components including columns, pontoons, and a platform assembly that can be constructed separately at conventional shipyards using readily available materials and equipment, then transported and assembled offshore in a controlled manner that minimizes weather impact.
Solution Approach 2:
Components are pre-assembled into modules onshore or in protected waters before transport to the final offshore location. This preliminary assembly reduces the complexity and duration of offshore operations, minimizing exposure to adverse weather conditions and reducing the need for expensive installation vessels.
3Device complexity
If conventional mooring systems are used, then the system is simple, but the mooring line is not securely held and hull stress increases due to repeated pushing and pulling
Solution Approach 1:
The mooring system uses spring mechanisms that act as mechanical counterweights to absorb and counteract the repeated pushing and pulling forces on the mooring line. These springs provide a cushioning effect that secures the mooring line while reducing stress transmission to the hull, eliminating the need for complex active tensioning systems.
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 design provides increased stability and cost-effectiveness during installation and decommissioning, reduces hull stress, and ensures secure mooring, enabling efficient and economical operation of large offshore wind turbines in challenging environments.
Implementation Method 1
The IASs are temporarily coupled to the hull during these operations to provide increased water plane area and/or buoyancy to the floating structure
Implementation Method 2
The chain engaging system is configured to lock the mooring chain to prevent it from moving lengthwise
Implementation Method 3
The mooring fixture is configured to pivot relative to the hull. The pivoting motion of the mooring fixture helps reduce shock loads on the hull that can occur due to strong winds and/or wave action
Data Source
AI summary
An offshore floating structure such as a wind turbine includes a number of improvements. The floating structure can include a chain engaging system configured to prevent any lengthwise movement of a mooring chain. The floating structure can also include a mooring fixture pivotally coupled to the hull to prevent shock loads from being transmitted directly from the mooring line to the hull. The floating structure can also include installation aid structures that provide additional water plane area and/or buoyancy to the structure. The floating structure can also have a hull that is optimized for use as an offshore wind turbine.