Coverbraid Rope Spiraling Strand Drag Reduction

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Solution Overview

Problem

The pelagic trawl industry faces high operational costs and drag issues due to the frequent damage and replacement of ropes used in forming pelagic mesh, leading to reduced profitability and environmental impact, as well as increased fuel consumption and marine mammal by-catch.

Innovation Solution

A rope construction with a spiraling strand of larger diameter and greater pitch than the other strands in the braided sheath, which is woven less frequently and with a more acute braid angle, reducing drag and maintaining lift while being stronger and less costly to manufacture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If coverbraided ropes are used in pelagic mesh, then strength and durability are improved, but manufacturing cost and complexity increase

Engineering Contradiction:

Improverope strengthVSAvoidmanufacturing cost

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The rope is segmented into distinct functional components: a core member providing structural strength and multiple sheath strands providing durability and protection. This segmentation allows each component to be optimized independently for its specific function while controlling overall manufacturing complexity

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The rope employs a composite structure combining a core member (such as wire or high-strength fiber) with sheath strands (such as polymer or textile materials). This composite construction achieves superior strength and durability by combining materials with complementary properties, resolving the contradiction between strength requirements and manufacturing feasibility

Inventive Principle:

Principle #40Composite materials

2Use of energy by moving object

If thin and light ropes are used to minimize drag, then fuel consumption is reduced, but rope strength and durability decrease

Engineering Contradiction:

Improvefuel consumptionVSAvoidrope strength

Core Design Contradiction:

Use of energy by moving objectVSStrength

Solution Approach 1:

The composite construction with a high-strength core member and protective sheath allows the rope to maintain high strength despite reduced overall diameter and weight. The core provides the necessary tensile strength while the sheath adds durability, enabling thinner, lighter ropes that reduce drag and fuel consumption without sacrificing strength

Inventive Principle:

Principle #40Composite materials

3Force

If helix ropes with larger diameter strands are used, then lift and drag reduction are improved, but splicing difficulty increases

Engineering Contradiction:

Improvelift forceVSAvoidsplicing ease

Core Design Contradiction:

ForceVSEase of repair

Solution Approach 1:

The rope structure is segmented into a core member and separate sheath strands, which simplifies splicing operations. The sheath strands can be individually manipulated and repositioned during splicing, making the process easier despite the presence of larger diameter strands that provide lift and drag reduction benefits

Inventive Principle:

Principle #1Segmentation

4Ease of manufacture

If non-jacketed braided twines are used, then manufacturing cost and splicing ease are improved, but drag and environmental impact increase

Engineering Contradiction:

Improvemanufacturing costVSAvoiddrag and environmental impact

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The composite construction with a protective sheath around the core member creates a more hydrodynamic profile that reduces drag compared to traditional non-jacketed twines. The sheath can be designed with smooth surfaces and optimized geometries that minimize water resistance and reduce environmental impact while maintaining cost-effectiveness

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 new rope design reduces drag and fuel consumption, enhances trawl opening efficiency, and improves environmental impact by minimizing by-catch and fuel usage, while maintaining the benefits of existing helix ropes, thus increasing market demand for self-spreading trawls.

Implementation Method 1

the braided sheath is formed of several strands and one of the strands is significantly larger in diameter than the other strands so as to form a series of cambered sections capable of either or both causing lift and/or reducing drag when such rope is subjected to water flow about the rope

Methodology Applied

Scientific EffectLift generation: Aerofoil

Implementation Method 2

Methodology Applied

Scientific EffectDrag reduction: Drag

Data Source

PatentUS10301773B2Coverbraided rope for pelagic trawls

Publication Date: 2019.05.28 HAMPIDJAN

AI summary

A rope has a braided sheath that includes a spiraling strand having a greater pitch in comparison with a pitch exhibited by other strands of a coverbraid that encloses that rope's strength member core. The rope is useful for forming pelagic trawl mesh, and is stronger for a given amount of material, has less drag, and exhibits the same or bettered lift when towed through water at trawl mesh angles of attack. The rope also is less costly to manufacture in comparison to known helix rope constructions.