Fiber-Optic Headline Sonar Cable for High-Resolution Trawl Data

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Solution Overview

Problem

Existing headline sonar cables made from steel are prone to damage, weight issues, and electromagnetic interference, which hinder the transmission of high-resolution data signals necessary for distinguishing between different fish species and sizes, leading to unintentional catches of non-target and juvenile fish.

Innovation Solution

A non-steel headline sonar cable with a fiber-optic conductor suspended in a helix form within a thermoplastic core, encased in a flexible material, and reinforced with a polymeric strength member, ensuring high signal resolution and durability under surging conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If steel is used for the cable strength member, then the cable has high strength and stiffness, but the cable becomes heavy and prone to electromagnetic interference and damage

Engineering Contradiction:
Improvecable strengthVSAvoidcable weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent replaces the traditional steel mechanical strength member with a synthetic fiber-based strength member (such as ultra-high molecular weight polyethylene or aramid fibers). This substitution eliminates the weight and electromagnetic interference problems associated with steel while maintaining the necessary strength and stiffness properties through the high strength-to-weight ratio of synthetic fibers.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent employs composite material construction by combining synthetic fiber strength members with polymeric insulation layers and protective jackets. This composite structure provides the necessary mechanical strength while avoiding the drawbacks of steel, and the layered polymeric composition provides electromagnetic shielding and corrosion resistance.

Inventive Principle:
Principle #40Composite materials

2Strength

If steel is used for the cable strength member, then the cable has high strength, but the cable is prone to damage from crushing forces and surging conditions

Engineering Contradiction:
Improvecable strengthVSAvoidcable durability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent changes the material parameters by transitioning from steel to synthetic fibers with different mechanical properties. The synthetic fibers (such as UHMWPE or aramid) have superior resistance to crushing forces and fatigue, and the polymeric insulation layers provide cushioning and protection against mechanical damage during surging conditions, thereby improving overall cable reliability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent incorporates polymeric insulation layers and protective jackets that act as cushioning elements before damage occurs. These layers absorb and distribute mechanical stresses, protecting the internal conductors and strength members from crushing forces and surging conditions that would otherwise cause damage.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Device complexity

If traditional cable construction is used, then the cable is simple in structure, but the cable cannot transmit high-resolution data signals for fish species differentiation

Engineering Contradiction:
Improvecable structure complexityVSAvoidsignal resolution
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces traditional metallic conductors with fiber-optic conductors that use light instead of electrical signals for data transmission. This substitution enables high-resolution signal transmission capable of supporting advanced sonar systems for fish species differentiation, while the polymeric insulation and protective layers provide the necessary electromagnetic shielding and mechanical protection.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Weight of moving object

If the cable uses synthetic polymeric material, then the cable becomes resilient to crushing forces and lighter, but the cable may lack the stiffness required for proper sonar operation

Engineering Contradiction:
Improvecable weightVSAvoidcable stiffness
Core Design Contradiction:
Weight of moving objectVSShape

Solution Approach 1:

The patent uses composite material construction where synthetic fiber strength members (providing light weight and crush resistance) are combined with polymeric insulation layers and protective jackets. The layered composite structure maintains cable stiffness through the combined properties of the materials, with the outer polymeric layers providing structural support and shape retention while the inner synthetic fibers provide tensile strength and light weight.

Inventive Principle:
Principle #40Composite materials

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 cable maintains high data signal quality and resolution, enabling accurate fish species and size differentiation, reducing unintended catches and improving fishing efficiency and marine ecosystem health.

Implementation Method 1

A data transmission cable, i.e. a headline sonar cable that is sometimes called a third wire, includes a conductor for transferring data signals from the headline sonar sensor to the towing vessel

Methodology Applied
Scientific EffectOptical fiber transmission: Optical Fibre

Implementation Method 2

A non-steel headline sonar cable with a fiber-optic conductor suspended in a helix form within a thermoplastic core

Methodology Applied
Scientific EffectHelical structure: Helix

Data Source

PatentEP3928138B1Improved high resolution headline sonar cable
Publication Date: 2026.04.15 HAMPIDJAN
  • EP3928138B1 patent drawingFigure 1
  • EP3928138B1 patent drawingFigure 1A
  • EP3928138B1 patent drawingFigure 2~3A

AI summary

Anon-steelheadline sonar cable is provided having a strength member (5) and a core (1), the headline sonar cable comprising a length of a core-cable (10), the length of core-cable (10) comprising core (1) as well as comprising at least onefiber-opticconductor (2) that is: (i) disposed in a helical shape; and (ii) completely encased in a solid, flexible material.Also provided is a process for making a headline sonar cable.The headline sonar cable is capable of being wound on a winch under tensions and surging shocks experienced by a fishing trawlerand provides high quality data signal transmission and resolution so as to permit usefor transmitting data from high-resolution sonars used to monitor fish caught in a fish trawl during operation.