Floating Wave Diffractor for Offshore Asset Protection
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Solution Overview
Problem
Current methods for servicing offshore or inshore constructions, such as maintenance, installation, or repair work, are limited by significant wave height and relative motions between the construction and the servicing vessel, with wave periods between 4 s and 10 s posing challenges due to inadequate wave subduing action, especially for vessels with widths less than 30 m.
Innovation Solution
A floating wave diffractor with a beam of 30 m or more is positioned transverse to the main wave direction to reduce wave height by diffraction, utilizing increased mass and mass moments of inertia, reduced stiffness, and viscous damping to minimize sway, roll, and heave motions, thereby extending the weather window for operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a vessel is used to subdue waves by positioning it along the wave crests, then shorter waves are subdued, but longer waves go under the vessel and lead to rolling action of the vessel
Solution Approach 1:
A floating breakwater is introduced as an intermediary object between the waves and the servicing vessel. The breakwater is positioned to intercept and subdue longer waves before they reach the vessel, preventing the rolling action that would otherwise occur. This intermediary structure allows the vessel to maintain stability while still benefiting from wave subduing action.
Solution Approach 2:
The breakwater's draught is adjusted to optimize its wave subduing capability. By changing the draught parameter, the breakwater can effectively intercept waves of different periods (4-10 seconds) while maintaining its position and stability. This parameter adjustment allows the breakwater to counteract longer waves without causing excessive rolling to the vessel.
2Object-affected harmful factors
If the width of the vessel is increased to improve wave subduing action, then wave subduing effectiveness increases, but the vessel becomes less maneuverable and more difficult to position
Solution Approach 1:
The wave subduing function is segmented from the servicing vessel and transferred to a dedicated floating breakwater. The breakwater is designed with specific dimensional characteristics (width between 5m-30m, preferably 10m-25m) that optimize wave subduing while maintaining maneuverability. This segmentation allows the vessel to focus on servicing operations without being constrained by the need for large dimensions for wave subduing.
3Object-affected harmful factors
If the draught of the vessel is increased to improve wave subduing action, then wave subduing effectiveness improves, but the vessel's stability and safety are compromised
Solution Approach 1:
The floating breakwater serves as an intermediary that performs the wave subduing function without requiring the servicing vessel to increase its draught. The breakwater's adjustable draught allows it to intercept waves effectively while the vessel maintains its own optimal draught for stability and safety. This separates the wave subduing requirement from the vessel's operational parameters.
4Duration of action of moving object
If a protecting vessel is positioned along the wave crests to subdue waves, then the weather window is extended, but the relative motion between the vessel and offshore construction increases
Solution Approach 1:
The floating breakwater acts as an intermediary that reduces wave height and relative motion between the servicing vessel and the offshore construction. By intercepting and subduing waves before they reach the vessel, the breakwater creates calmer conditions that extend the weather window while minimizing harmful relative motions during operations.
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 solution effectively reduces wave height by up to 50% for wave periods between 4 s and 10 s, increasing the weather window for maintenance and repair operations by 67% or 20% points, allowing safer and more efficient operations within a wider safe condition window.
Implementation Method 1
A floating wave diffractor with a beam of 30 m or more is positioned transverse to the main wave direction to reduce wave height by diffraction
Implementation Method 2
utilizing increased mass and mass moments of inertia, reduced stiffness, and viscous damping to minimize sway, roll, and heave motions
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Method to facilitate operations in connection with fixed or floating offshore assets including determining a main wave direction, providing a floating wave diffractor having a length and a width, wherein the length of the floating wave diffractor is greater than the width of the beam of the floating wave diffractor, positioning of the floating wave diffractor against the main wave direction in front of at least one fixed or floating asset, wherein the positioning includes moving the floating wave diffractor in the longitudinal and transverse direction of the floating wave diffractor and rotating the floating wave diffractor, wherein the wave diffractor is positioned substantially transverse to the main wave direction, wherein the floating wave diffractor has a beam width of 30 m or more, in particular, such that at least the height of waves of having period between 4s and up to 10 s are is reduced by the floating wave diffractor.