Trawl Door with Remotely Controlled Flaps for Stability
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Solution Overview
Problem
Trawl doors face instability and inefficiency at larger angles of attack, especially at slower towing speeds, leading to increased drag and potential tangling, and require varying opening parameters for different fisheries, necessitating a solution that enhances stability and efficiency across speed and angle ranges without significant size increase.
Innovation Solution
A trawl door design based on curved airfoils with remotely controlled flaps and adjustable panels, utilizing aeronautical principles for maximum lift and minimum drag, allowing for vertical and horizontal adjustments to enhance spreading ability and stability, particularly at high angles of attack and slower speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If trawl doors operate at larger angles of attack to maintain stability under destabilizing forces, then stability is improved, but drag increases and efficiency decreases
Solution Approach 1:
The patent applies dynamics by making the trawl door's angle of attack adjustable rather than fixed. The door can dynamically change its orientation angle in response to varying operating conditions (speed, depth, sea state), allowing it to maintain stability when needed while minimizing drag during efficient towing. This dynamic adjustment resolves the contradiction between stability and energy loss.
Solution Approach 2:
The patent changes the operational parameter of angle of attack to optimize performance. By varying this parameter based on towing speed and fishing conditions, the system can achieve both stability at low speeds and efficiency at high speeds, resolving the contradiction between these two opposing requirements.
2Adaptability or versatility
If trawl doors are designed for high vertical opening with less spread, then vertical opening capability is improved, but water resistance increases
Solution Approach 1:
The patent makes the trawl door system universal by enabling it to perform multiple functions through angle adjustment. The same door can be configured for high vertical opening with less spread when needed, or adjusted to provide maximal spread for wide body trawls, adapting to different fishing requirements without being locked into a single configuration that would always incur high resistance.
3Adaptability or versatility
If trawl doors are designed for maximal horizontal opening with maximal spreading forces, then horizontal opening capability is improved, but device complexity increases
Solution Approach 1:
Rather than designing complex mechanical systems with multiple fixed configurations, the patent uses dynamic angle adjustment to achieve different opening capabilities. This simpler dynamic approach replaces what would otherwise require complex multi-configuration mechanical systems, reducing overall device complexity while maintaining versatility.
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 improved trawl door design achieves enhanced stability and reduced drag at high angles of attack, maintaining operational orientation under destabilizing forces and operating efficiently across a range of speeds and angles, while maintaining a comparable size to existing doors.
Implementation Method 1
The door is based upon curved airfoils to give maximum lift force and minimum drag
Implementation Method 2
The remote wireless or wired controlled flaps give the opportunity to increase the lift force, and thereby increase the spreading ability of the doors
Implementation Method 3
The door is based upon curved airfoils to give maximum lift force and minimum drag
Implementation Method 4
the flaps (9) adapted to be controlled remotely, when the device is in use being towed through the water
Data Source
Figure 1
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AI summary
There is provided a spreading device, such as a trawl door (1) used for trawl fishing, and more particularly, a trawl door (1) adapted for stable and efficient operation. The door (1) is equipped with flaps (9) mounted below distal panels (6, 8) and connected to driving units, and the flaps (9) are adapted to be controlled remotely, when the spreading device is being towed through the water; the lower distal panel (6) and the upper distal panel (8) have distal surfaces (6', 8') rendering them hollow, wherein the flaps (9) constitute a part of the distal surface.