Outboard Deck Anchoring for Side-by-Side Mooring Stiffness
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Solution Overview
Problem
Existing side-by-side mooring configurations for hydrocarbon vessels are limited in operational availability due to disconnection requirements in sea states higher than 2 m significant waves, and they are not effective for vessels of different sizes or in harsher environments, limiting reliable mooring and fluid transfer.
Innovation Solution
The offshore structure features quick release members with bow and stern anchoring points on outboard decks, allowing horizontal anchor line configurations that provide maximum mooring stiffness and flexibility, accommodating vessels of varying sizes with a combination of steel and synthetic rope mooring lines, and a telescopically extendible transfer arm for hydrocarbon transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anchor lines are positioned on the main deck at standard height, then the structure is simple and easy to manufacture, but the mooring stiffness is reduced and wear on synthetic rope material occurs due to contact with the deck
Solution Approach 1:
The patent positions anchoring points on outboard decks that extend laterally from the main hull, moving the anchor line attachment from the horizontal deck plane to a vertically elevated and laterally extended position. This dimensional change allows anchor lines to clear the main deck surface, eliminating wear on synthetic rope material while maintaining mooring stiffness through optimized line geometry.
Solution Approach 2:
The outboard deck acts as an intermediary structure that carries the anchoring points away from the main hull. This intermediate platform allows the anchor lines to be positioned optimally for both stiffness and wear prevention without requiring modification to the main deck structure, thus resolving the contradiction between reliability and complexity.
2Duration of action of stationary object
If the anchoring points are positioned on outboard decks, then wear on synthetic rope material is prevented, but the structure becomes more complex and requires additional deck space
Solution Approach 1:
The deck structure is segmented into the main deck and separate outboard decks that extend laterally from the hull. This segmentation allows the anchoring points to be positioned on the outboard sections, which occupy minimal additional space while providing the necessary clearance for anchor lines. The outboard decks can be designed as compact structures that minimize footprint while achieving the wear prevention objective.
3Reliability
If anchor lines are configured at steep angles, then the structure is simpler, but the mooring stiffness is reduced and freedom of motion is overly constrained
Solution Approach 1:
The patent optimizes the geometric parameters of the anchor line configuration by positioning anchoring points on outboard decks at specific heights and lateral distances. This parameter optimization achieves near-horizontal line angles that maximize mooring stiffness while preserving adequate freedom of roll, pitch, and sway motions. The specific positioning parameters are selected to balance stiffness requirements with operational flexibility.
4Adaptability or versatility
If the structure is designed to accommodate vessels of different sizes, then versatility is improved, but the mooring configuration becomes more complex
Solution Approach 1:
The outboard deck anchoring system provides a universal mooring solution that can accommodate vessels of various sizes and types. The elevated and laterally extended positioning of anchoring points creates a flexible geometric configuration that can be adapted to different vessel dimensions without requiring multiple specialized mooring systems. This multi-functional design achieves versatility while maintaining relatively simple structural elements.
Data Source
AI summary
The invention relates to a floating offshore structure anchored to the sea bed. The floating offshore structure comprises a hull having longitudinal sides and transverse sides, bow and stern anchoring points for mooring a tanker vessel alongside the offshore structure, a deck at a predetermined height above sea level, hydrocarbon storage and/or processing devices being placed on the deck, a spacer member attached to the structure and projecting transversely from the sides for contacting a tanker vessel moored alongside the structure. The anchoring points of the structure comprise of quick release members, wherein the bow and/or stern anchoring points of the structure are situated on a deck which projects transversely from the hull of the structure substantially at the heights of anchoring points of the tanker vessel.