Multi-foil Lift Force Creator for Fishing Trawl
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Solution Overview
Problem
The existing methods for providing vertical force on a fishing trawl net, relying on spherical buoyancy elements, face disadvantages such as constant buoyancy force and velocity-dependent hydrodynamic forces, leading to suboptimal trawl net opening and increased drag, with spherical floats occupying more space than necessary and being prone to entanglement.
Innovation Solution
A multi-foil lift force creator comprising a plurality of hydrofoil elements stacked and attached rigidly to spherical buoyancy or gravity elements, creating complementary hydrodynamic lift forces that balance buoyancy forces, maintaining dynamic equilibrium and reducing drag, while occupying minimal space and preventing entanglement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If spherical buoyancy elements are used to provide vertical force on the trawl net, then the trawl net can be opened vertically, but the buoyancy force remains constant regardless of towing velocity, leading to suboptimal performance at varying speeds
Solution Approach 1:
The buoyancy system is segmented into multiple functional components: spherical buoyancy elements for constant upward force and hydrofoil elements for velocity-dependent lift force. This segmentation allows each component to contribute differently based on towing velocity, with hydrofoils providing increasing lift as velocity increases, thereby achieving adaptability across varying speeds while maintaining optimal trawl net opening efficiency
Solution Approach 2:
The system transitions from a static buoyancy-only approach to a dynamic system where hydrofoil elements generate lift forces that vary with towing velocity. The hydrofoils are rigidly connected to the buoyancy elements, creating a composite structure where the upward force dynamically adjusts to velocity conditions, improving productivity across different operational speeds
2Force
If multiple spherical floats are tied in a row to provide sufficient vertical forcing, then the trawl net can be opened, but the floats occupy excessive physical space and are prone to entanglement
Solution Approach 1:
The invention merges the functions of spherical buoyancy elements and hydrofoil elements into a single integrated lift force creator assembly. The hydrofoils are rigidly connected to the buoyancy elements at both ends, combining the constant buoyancy force with velocity-dependent hydrodynamic lift. This merger achieves the required vertical forcing while occupying significantly less space than multiple separate floats, and the streamlined configuration reduces entanglement risks
Solution Approach 2:
The solution transitions from a one-dimensional arrangement of multiple spherical floats tied in a row to a more compact three-dimensional integrated structure. The hydrofoil elements are stacked and arranged in a configuration that maximizes vertical force generation while minimizing the horizontal space occupied, thereby reducing both volume occupancy and entanglement susceptibility
3Reliability
If spherical floats made from hard plastic are used to operate at depths below 1000 meters, then durability is achieved, but the upward force provided is small relative to the physical space occupied
Solution Approach 1:
The system uses a composite approach combining spherical buoyancy elements (made from durable hard plastic for reliability at depth) with hydrofoil elements (made from rigid yet hydrodynamically efficient materials). This composite structure leverages the strength and durability of the spherical elements while the hydrofoil elements provide enhanced upward force through hydrodynamic lift, achieving high upward force per unit volume without compromising operational durability at depths below 1000 meters
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 multi-foil lift force creator significantly increases vertical forcing, maintains optimal trawl net shape across varying velocities, and reduces drag, providing a scalable and efficient solution for trawl net operation by leveraging hydrodynamic lift forces without increasing space occupancy or entanglement risks.
Implementation Method 1
the hydrofoil elements are shaped to deflect the water during towing of the trawl net in such a way that the hydrodynamic force thereby created complements the buoyancy force from the buoyancy elements
Implementation Method 2
The force provided by the floats is an upward buoyancy force due to the entrapped content of air within the floats
Implementation Method 3
the working principle of trawl doors providing the outward-directed lateral spreading forces on the trawl net is based on hydrodynamic lift forces
Implementation Method 4
maintains optimal trawl net shape across varying velocities, and reduces drag
Data Source
Figure 1~2
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Figure 5~6
AI summary
A multi-foil lift force creator (1) for a fishing trawl is disclosed, said multi-foil lift force creator comprising a plurality of hydrofoil elements (2) aligned in a stacked manner and designed to be arranged between and attached rigidly at both ends to a spherical buoyancy element (9) for being mounted on a fishing trawl head rope (11), wherein the hydrofoil elements are shaped to deflect the water during towing of the trawl net (12) in such a way that the hydrodynamic force thereby created complements the buoyancy force from the buoyancy elements, and wherein, rather than having butt ends, the hydrofoil elements join smoothly to multi-foil end caps (5) fitting tightly around the two buoyancy elements at the ends of the multi-foil lift force creator, respectively. Furthermore, a multi-foil lift force creator assembly comprising such a multi-foil lift force creator and the use of such multi-foil lift force creator assemblies during trawling operation are disclosed.