Fish Descending Device with Rotating Hook
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Solution Overview
Problem
Existing descending devices for fish suffering from barotrauma are cumbersome and dangerous to use, as they require holding the fish and weight in an awkward position, leading to potential loss of the fish if not positioned correctly during lowering, resulting in reduced survival rates and unsustainable fish stocks.
Innovation Solution
A descending device featuring a bent wire with a slide ring and weight attachment, allowing the fish to be securely hooked and lowered without falling off, with the weight ensuring proper positioning and depth control, enabling easy operation by one person even on boats with high gunnels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an upside down hook with weight is used as a descending device, then the fish can be returned to depth, but the device becomes cumbersome and dangerous to use
Solution Approach 1:
The hook is designed to rotate 180 degrees during deployment, transforming from an upside-down position (difficult to control) to a right-side-up position (easy to control). This dynamic reorientation allows the fish to be securely attached initially, then automatically positions the hook for safe retrieval without requiring awkward manual positioning throughout the process.
2Ease of operation
If the fish is tossed into water from a boat with high gunnels, then the fish must land in the correct position, but this increases the risk of the fish falling off the hook and floating away
Solution Approach 1:
The hook is pre-configured in an upside-down position that naturally guides the fish onto the hook during the tossing motion. The weight is positioned to ensure the device orients correctly upon water entry, automatically securing the fish before retrieval begins. This preliminary configuration eliminates the need for precise manual positioning during deployment.
3Reliability
If the fish is held in an awkward position during lowering, then the descending device can function, but this increases the danger and complexity of operation
Solution Approach 1:
The device utilizes dynamic reorientation where the hook rotates 180 degrees during deployment, transforming from an awkward upside-down position to a convenient right-side-up position. This dynamic transformation maintains descending functionality while eliminating operational complexity and safety hazards associated with holding the fish in awkward positions throughout the process.
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 device ensures safe and efficient return of fish to depth, reducing barotrauma and maintaining healthy fish stocks by preventing fish loss during descent, allowing for successful reproduction and keeping fishing areas open.
Implementation Method 1
the weight of the fish ensures that the wire is pulled down on the slide ring
Implementation Method 2
the fish, which is now more buoyant that the weight due to the expanding gases in the fish's swim bladder
Data Source
AI summary
A descending device including a member providing a fish attachment point, a member providing a means of traversing the suspension point, a moveable member to attach the suspension line and traverse to the alternate suspension point, a member that applies a moment about a suspension point to reverse the orientation of the device and stops that prevent the attachment member from coming off the descending device.