Lines

Examples of lines
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Description

Line is the term for a rope used in aquatic applications. A line is a cord made by twisting or braiding together natural or synthetic fibers. Lines can be braided, twisted, twisted composite, and have lead or foam centers. There are many types of lines, each with advantages, disadvantages, appropriate uses, and sometimes safety implications.

Lines Overview
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Lines Overview

VIDEO LINK: https://youtu.be/4rIowvvUvFc

Braided line: made from multiple strands that are woven together
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Braided line: made from multiple strands that are woven together

A twisted Polydacron line with black-colored tracer used to identify the manufacturer.
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Twisted line: usually made by twisting three strands together to create a spiral pattern.

A twisted Polydacron line with black-colored tracer used to identify the manufacturer.

Nylon Overview and Safety Issues
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Nylon Line

Generally not recommended for fishing gears; except for tying boats to docks; do not use as a tow line unless using larger diameter line and/or smaller trawls as typical of hand bow trawling; maybe not good for anchor line; builds up kinetic energy when stretches; line breaks and whips back which is a safety issue. Specific gravity is around 1.14, so nylon line sinks but slowly.

VIDEO LINK: https://youtu.be/iiH2BCH_5ac

Nylon Line Story
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Nylon Line Story

VIDEO LINK: https://youtu.be/oyQt1LmUVn0

Polypropylene Line
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Polypropylene Line

Polypropylene line is a very common rope; twisted or braided; good utility rope, for general use; lots of uses as rope and line, towing small bow trawls, mini-Missouri trawls, bottom trawls, and pull seines. Specific gravity is 0.96 – 0.98, therefore this line type will float. Another advantage is the low cost of polypropylene.However, polypropylene line is UV susceptible and has a low abrasion resistance so this line should be examined frequently. 

VIDEO LINK:https://youtu.be/DDskvOV34WI

Hollow Braid Polypropylene Line
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Hollow-braid Polypropylene Line 

  • Hollow-braid polypropylene line is very commonly used; minimal tensile strength, easily spliced, good all-around rope; good utility line
  • Used for gill nets, trammel nets, seines
  • Specific gravity is 0.96 -0.98 (floats).
  • Economical, easy to work with.
  • Minimal strength.

VIDEO LINK: https://youtu.be/NGCvTjHw9iA

Polyester Dacron Line
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Polyester Line (Dacron)

Polyester line is braided and comes in a squarish shape; thus, it is a good line for hauling by hand.It does stretch, less-so than nylon, but can store up significant kinetic energy, break and whip backward endangering crew, particularly if attached to a metal structure. Another braided line type would be preferable safety-wise; do not put polyester line under constant strain. 

  • Specific gravity is 1.35 – 1.38, thus this line type sinks.
  • Good resistance to chaffing.

VIDEO LINK: https://youtu.be/UjWGvCCLd4o

Polyester Line (Dacron)
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Polydacron Line

A combination made of Dacron [= polyester] and polypropylene. The structure is dacron wrapped polypropylene.The black marker is a tracer (identifies the line manufacturer; but beware of tracer imitators that could be inferior quality). Dacron gives the line abrasion resistance; the polypropylene provides strength and keeps the rope from being unraveled. Specific gravity is 1.38 (will sink readily). Polydacron line will stretch about 20% before breakage. Good all-around rope, safely used for some trawls, tow lines, certain seines; there are many manufacturers.

VIDEO LINK: https://youtu.be/I3-4ctCfBhk

Polyethylene Braided Line
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Polyethylene Braided Line

  • This line is an 8-strand by 2, braided cord.
  • Proper uses include as tow lines, for small purse seines, hanging small to medium seines, trawl headropes and footropes.
  • PE braided line has low stretch.Specific gravity is around 0.98 (floats)
  • PE braid is hollow, so it can be spliced through and through or inside; this line type is easy to splice.

VIDEO LINK: https://youtu.be/dgm0y7sRe-c

Dyneema
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Dyneema

This line is as strong as steel cable.A 5/16” diameter, 8 strand Dyneema line has a minimum pull before breakage 14,000 pounds, can handle 7 tons before line breaks; 1/2” pulls >20 tons; Dyneema is the strongest rope in the world. 

  • Rope is tough and has a low weight.
  • Slippery to feel, and has special procedures for splicing; tucked, spiked (fid weaved through placing threads to prevent slip); a splice is 95% as strong as original un-spliced line.
  • Knots will slip and self-open, thus do not tie knots on the line.
  • Optimal use is as a tow line. If you are towing anything deeper than 500’, use Dyneema line.Dyneema line can tow anything; it replaces nylon and steel cable.

VIDEO LINK: https://youtu.be/xK2VUF2fK3A

Leadcore
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Leadcore

Leadcore contains a chain of lead pellets in the center, usually having a polyester cover or wrapping.This line is somewhat flexible.It is desirable to have a quality line where the polyester cover holds tightly to the lead pellet chain and has some flexibility.Lead pellet leadcore lays flat and has better bottom contact as opposed to line with lead weights (“balls”).

  • Leadcore line rolls nicely on net reels.
  • It comes in different diameters (1/8” and up).
  • Used in nets (gill nets, trammel nets, purse seines, etc.).

VIDEO LINK: https://youtu.be/VJC01P1xEF0

Foamcore
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Foamcore

Foam core rope showing floatation material, the foam core.

The floatation foam is in the middle. Foamcore takes the place of floats. A significant advantage is that buoyancy is distributed evenly.

Disadvantages

  • Doesn’t float well (one linear foot floatation similar to two small sp3 floats)
  • Foamcore will stretch and stretch
  • If the foam breaks, and the line stretches, the foam will retract leaving a gap and no floatation in that gap section of the line.

Foamcore is not meant to be tugged on.Uses are mostly for nets that sink to the bottom, for holding nets vertical when in contact with the bottom (not for floating entire net at or near water surface). However, foamcore can be used for light weight floating gill and trammel nets.

It comes in many sizes, 3/8”, 1/2", 3/4", 1”, etc.

Foamcore
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Foamcore Line

VIDEO LINK: https://youtu.be/Yyn0iYONBjs

Combination Line

Combination rope showing steel core
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Combination rope showing steel core.

“Combination Rope” (rope and steel cable on inside); 6 strands of polyester and polypropylene twine, each strand wrapped around stainless-steel wire; all the polyester/polypropylene/steel strands are wrapped around a very tightly wound single strand of polypropylene line at the very core or center (holds the other six strands in place, gives continuity); example is 1/2”, 5/16” are good sizes for trawls.

Danish cable (colored blue and white) high quality (shown in video)

Advantages

  • Durability, tough
  • Can take a lot of tension, virtually no stretch.
  • Does not rotate, netting stays in place where attached to line.
  • Can be swaged (cable looped back on itself and held with copper bands) or hand spliced.
  • Stiffness of cable helps open net mouth.
  • Can haul larger trawls (125’ easily).

Disadvantages

  • Stiff; doesn’t fold up nice and flat as a regular line would.
  • Not easy to tie knots.
  • Hard to free from snags.

Applications

Bigger operations. Specifically, for hanging the headropes and footropes of large trawl nets (for the Great Lakes [Yankee trawls], Gulf of Mexico, Atlantic Ocean).

Combination Line
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Combination Line

VIDEO LINK: https://youtu.be/bdF41R-xs94

Rope Evaluation
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Rope Evaluation

VIDEO LINK: https://youtu.be/chFvAC2UpII

Stowage
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Rope Storage

VIDEO LINK: https://youtu.be/3wAwtO_dUZ0