Cantilevered Mooring Beam Stabilizes Floating Base
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Solution Overview
Problem
Current floating and semi-submerged renewable energy devices, such as wave-energy-converters (WECs) and offshore wind-turbines (FWTs), face inefficiencies due to undesirable wave and wind-induced motions like heave, surge, and pitching, which reduce energy capture efficiency and increase capital expenditure.
Innovation Solution
A motion-stabilized floating or semi-submerged base system utilizing a cantilevered mooring beam connected to a submerged mooring buoy anchored to the seabed by a tensioned leg or cable, allowing self-orientation into oncoming waves and wind gusts, and incorporating adjustable mooring beam length and seawater ballast for optimal stabilization and energy capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a floating or semi-submerged base is used for WEC or FWT, then deployment in deep water (>50m) is enabled, but wave and wind-induced motions (heave, surge, pitching) increase, reducing energy capture efficiency
Solution Approach 1:
The patent employs a tensioned leg or cable system that acts as a counterbalancing mechanism, providing restoring forces against wave and wind-induced motions. The tensioned mooring system creates a stabilizing effect that counteracts the destabilizing forces of heave, surge, and pitching motions, thereby maintaining energy capture efficiency while enabling deep water deployment.
Solution Approach 2:
The cantilevered mooring beam serves as an intermediary structural element between the floating base and the tensioned leg/cable system. This intermediate component transmits and distributes the stabilizing forces from the mooring system to the base, effectively mediating the interaction between the floating structure and the environmental forces, thus reducing unwanted motions while maintaining deployment capability.
2Stability of the object's composition
If traditional stabilization methods are used, then motion stability is improved, but structural mass and capital expenditure increase
Solution Approach 1:
The patent extracts the stabilization function from the primary structural mass of the floating base and relocates it to an external tensioned leg or cable system. By separating the stabilization mechanism from the base structure itself, the design achieves motion stability without requiring excessive structural mass in the floating base, thereby reducing capital expenditure while maintaining stability.
Solution Approach 2:
The stabilization system combines different structural elements (cantilevered mooring beam, tensioned leg/cable, anchoring system) into a composite stabilization architecture. This composite approach distributes the stabilization function across multiple components with optimized mass characteristics, achieving effective motion control without concentrating excessive mass in a single structure, thus reducing overall structural mass requirements.
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
This solution minimizes structural mass and capital expenditure while enhancing energy capture efficiency by stabilizing the base against wave and wind-induced motions, allowing for maximum wave energy interception and reducing pitching and heaving effects.
Implementation Method 1
anchored to the seabed by a tensioned leg or cable
Implementation Method 2
buoyant wave energy converter or floating wind turbine base
Data Source
AI summary
A device to stabilize, reduce, or control the wave or wind-induced heave (vertical), surge (lateral), or pitching (rolling) motion of a floating or semi-submerged buoyant base, raft, barge, buoy or other buoyant body such as the buoyant base of a wave energy converter or a floating wind turbine base. The device concurrently allows the floating base to self-orient or weathervane to substantially maintains its orientation with respect to the direction of oncoming waves, winds, or wind gusts. The device also facilitates maintaining the submerged depth or vertical orientation of the buoyant base relative to the still water line to compensate for tidal depth changes. The device utilizes a second substantially submerged buoyant body having a center of buoyancy and at least one tensioned seabed connection located substantially below and forward or up-sea or up-wind of the center of buoyancy of the buoyant base. A structural member, which can optionally also be buoyant or integral with the base or second submerged body, connects the submerged buoyant body with the floating base.