Rotatable Connector Assembly for Offshore Vessel Mooring
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Solution Overview
Problem
Existing mooring systems for offshore vessels have limitations in weathervaning capability, are costly, and require complex and invasive installations, making them unsuitable for short- and medium-term installations such as Extended Well Tests and Early Production Systems.
Innovation Solution
A connector assembly with a rotatable design allowing the vessel to swivel about the mooring coupling, featuring a hollow swivel connector assembly with water-lubricated bearings and a guide for fluid transfer conduits, enabling unlimited weathervaning and quick disconnect/reconnect operations with reduced capital and operating costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a three-leg mooring system with flexible riser is used, then the structure is relatively simple, but the weathervaning capability is limited and fatigue and wear problems occur
Solution Approach 1:
The connector assembly employs a nested structure where an inner cylindrical connector is positioned within an outer cylindrical connector. The inner connector rotates freely within the outer connector, allowing the riser to weathervane independently while maintaining structural simplicity. This nested arrangement enables unlimited rotational movement without requiring complex external mechanisms.
2Adaptability or versatility
If unlimited weathervaning capability is achieved, then the vessel can rotate freely, but heavy and sophisticated structures with high capital cost are required
Solution Approach 1:
The connector assembly is divided into distinct functional segments: an outer cylindrical connector for structural support and mooring line attachment, an inner cylindrical connector for riser connection and rotation, and bearing assemblies positioned between them. This segmentation allows each component to perform its specific function efficiently, enabling unlimited weathervaning through the inner connector's rotation while keeping the overall structure relatively simple and cost-effective.
3Adaptability or versatility
If internal turret systems are used, then full weathervaning is enabled, but capital expenditure exceeds $30m for turret fabrication and integration
Solution Approach 1:
The invention extracts the essential weathervaning function from the complex internal turret system and implements it through a simpler connector assembly mounted on the vessel bow. The connector assembly provides the necessary rotational capability through its nested cylindrical design with bearings, eliminating the need for expensive turret fabrication and integration into the vessel hull while achieving the same unlimited weathervaning capability.
4Ease of manufacture
If external turret arrangements are used, then implementation is less invasive, but capital expenditure remains high
Solution Approach 1:
The connector assembly represents a more economical alternative to external turret systems, using simpler materials and construction methods. The assembly employs standard bearing components and cylindrical structures that can be manufactured and installed at a fraction of the cost of external turret arrangements, while providing equivalent functional performance for the intended application duration.
5Adaptability or versatility
If CALM buoy systems are used, then mooring is achieved, but structural buoyancy and multiple mechanical parts increase complexity and fabrication costs
Solution Approach 1:
The invention extracts the essential mooring and rotation functions from the complex CALM buoy system and implements them through a streamlined connector assembly. The connector provides direct mooring line attachment and riser connection with rotational capability, eliminating the need for submerged buoy structures and multiple mechanical components while achieving the same operational capability.
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 provides a robust, economical, and efficient mooring solution with unlimited weathervaning capability, facilitating easy installation and recovery, and allowing vessels to be reassigned for ordinary ocean transport, suitable for various offshore applications including Floating Production Storage and Offtake systems.
Implementation Method 1
The connector assembly comprises water-lubricated bearings
Data Source
AI summary
A mooring system, and connector assembly, which in a preferred embodiment is a vessel mooring and fluid transfer system. The connector assembly has a first portion (2A) configured to be coupled to one or more mooring lines (1), and a second portion (2B) configured to be coupled to a vessel. The first and second portions are rotatable with respect to one another to permit a vessel coupling on the second portion to swivel about the mooring coupling on the first portion. In a preferred embodiment, the connector assembly comprises a guide (2E) for a conduit, which may be a fluid transfer conduit such as flexible riser (6). The invention also provides methods of use of the mooring systems described.