One-Side Spread Mooring Layout for Side-by-Side FLNG Offloading
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Solution Overview
Problem
Existing spread mooring systems for Floating Liquefied Natural Gas (FLNG) vessels cause interference with cargo carriers during side-by-side offloading, necessitating expensive turret equipment and increased capital expenditures.
Innovation Solution
A one-side spread mooring system is applied to FLNG vessels, with mooring lines fastened to one side of the hull, spreading in opposite directions to create sufficient clearance for side-by-side offloading, eliminating the need for turret equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spread mooring is applied to FLNG vessel, then capital expenditure is reduced, but interference occurs between carrier and mooring lines preventing side-by-side offloading
Solution Approach 1:
The mooring system is segmented into two distinct groups: first mooring lines extending from the first location and second mooring lines extending from the second location. This segmentation allows the carrier to approach from a direction that avoids interference with either group, enabling side-by-side offloading while maintaining the cost-effective spread mooring configuration
Solution Approach 2:
The patent employs asymmetric mooring line arrangement where the first and second mooring lines are positioned at different locations and extend in different directions. This asymmetric configuration creates an interference-free zone that allows carrier approach and docking for side-by-side offloading, resolving the contradiction between cost reduction and operational capability
2Ease of operation
If turret mooring is applied to enable side-by-side offloading in harsh marine environment, then operational capability is improved, but capital expenditure increases due to expensive turret equipment
Solution Approach 1:
The patent replaces expensive, complex turret equipment with simpler, more economical spread mooring lines that achieve the same side-by-side offloading capability. The mooring lines are conventional components that are less costly than turret systems, while still providing the necessary operational flexibility in harsh marine environments
Solution Approach 2:
The patent extracts and eliminates the need for expensive turret equipment by using a simplified mooring line configuration. The turret function of enabling rotation and side-by-side offloading is achieved through the geometric arrangement of mooring lines rather than mechanical turret systems, significantly reducing capital expenditure
3Ease of manufacture
If spread mooring is applied to FPSO vessel, then capital expenditure is reduced compared to turret mooring, but interference occurs between carrier and mooring lines
Solution Approach 1:
By segmenting the mooring lines into two separate groups at different locations, the patent creates distinct operational zones that prevent carrier-mooring line interference. The carrier can approach from a direction that avoids both the first and second mooring lines, eliminating the harmful interference effect while maintaining the economical spread mooring design
Data Source
AI summary
A floating offshore structure to which a one-side spread mooring system is applied is provided. The floating offshore structure includes: first mooring lines fastened to one of a port and a starboard of a hull, the first mooring lines being spread out in a first direction, which is a direction away from the hull, into a seabed; and second mooring lines fastened to the same side of the hull as the first mooring lines, the second mooring lines being spread out in a second direction, which is a direction toward an opposite side of a centerline of the hull to the first mooring lines, into the seabed through a lower space of the hull.