Ropes and Fibers - cfcc. MSC 132 Fishing Gear Technology I With Excerpts from:...

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Transcript of Ropes and Fibers - cfcc. MSC 132 Fishing Gear Technology I With Excerpts from:...

  • MSC 132

    Fishing Gear Technology I

    With Excerpts from:

    Fishermans Workbookcompiled by J. Prado, Fishing News Books, Oxford:1990

    Yale Cordage Ropes For Industry2nd. Edition,Yale Cordage Inc., Yarmouth, ME.:1985

    Ropes and Fibers

  • Constructions: Each type of line has its special characteristics; therefore, by knowing the type of material and the method of manufacture, you can decide on the particular rope for your desired use.

    3-Strand The original rope construction is the simplest

    type of rope. It is formed by

    twisting fiber into a strand.

    Three formed strands are then

    twisted to produce the finished

    rope. It is a spliceable rope.

    Single Braid This construction

    leaves a void in the center and

    utilizes strand counts of 8, 12, or 16.

    The hollow is instrumental in the

    easy splice procedure. Hollow braids

    are non-rotational and are an efficient

    way to utilize fiber. It is a spliceable

    rope.

    Double Braid This is

    really two separate ropes in

    one. The core, which is a

    single braid, is over braided

    with a second sleeve. This

    construction allows maximum

    flexibility options to utilize the

    same or dissimilar fibers. This

    construction entirely shields

    one of the two rope elements

    from abrasion. It is a

    spliceable rope.

  • Constructions: Always consult the manufacturer before using rope when personal safety or possible damage to property is involved. Make sure the rope is adequate for the job. Do not use too small a rope or the wrong type.

    Solid Braid This rope is also called

    Sash Braid Rope.

    Solid braid ropes are

    constructed of various

    bundles of fiber

    interlocked together in

    a circular braiding

    pattern. They are not

    spliceable.

    Plaited Rope 8Eight strand square

    braid is comprised of 8

    individual strands which

    are woven together as 4

    pairs. Its strength is

    virtually identical to 3

    strand with its major

    advantage being its non-

    rotating characteristics.

    Diamond Braid ropes are constructed from

    various bundles of fiber

    braided in a herringbone

    pattern to form a jacket

    over a parallel fiber center

    core. These are also

    referred to as mayploe

    braids and are not

    spliceable.

    Parallel Core This construction consists of a

    core of parallel yarns that

    are held together by a

    wide variety of different

    means from extrusion to

    braiding. Due to its low

    twist level, these ropes are

    usually very strong but

    have limited applications

    due to loss of strength in

    bending and termination

    constraints.

  • Material: Once a rope construction is selected for a particular use, you must decide on the kind of material or fiber.

  • Material: Most manufacturers provide specification sheets and/or generalized fiber selection tables. Tables are

    also available in a variety of reference books.

    *Class HandoutManufacturers Examples

  • Manufacturers Selection Guide**Rhino Ropes, Wellington Commercial Products General Catalog

  • Class Handout Selection Guide

  • Material Identification: You may encounter a pre-existing rope and/or fiber that you cannot identify. Guides and

    specific testing indicators may help with your assessment.

  • Strength and Size Selection

  • Class Handout Selection Guide

  • Class Handout Selection Guide

  • General Rope Usage

  • *Multiplication factor used to calculate the

    weight in water of different materials.

    Sinking Materials

    Floating Materials

  • P = A x {1 DW/DM}*Where:

    P = weight (kg) in water

    A = weight (kg) in air

    DW = density (g/cc) of water (freshwater 1.00; sea water 1.026)

    DM = density (g/cc) of material

    *The term in brackets, the multiplication factor, has been calculated for the

    materials most commonly used in

    fisheries, with the results given in the

    Density of Materials table. The factor

    followed by a + sign indicates a sinking

    force. The factor followed by a sign

    indicates a buoyant or floating force. To

    obtain the weight in water of a certain

    quantity of material, simply multiply its

    weight in air by the factor. *The same

    multiplication factor can be used with

    either the metric or the customary

    system of measurement.

  • Calculation Examples:

    Air Weight and Weight in Water Fiber Cordage: Typical Weights

    Nylon (PA): O , 1 circ.

    Net Weight per 100 = 6.6 lbs.

    Feet per Pound = 15

    Breaking Strength = 6,650 lbs.

    60 feet of this rope weighs?

    Air Weight =

    6.6 lbs. 100 ft. = .066 lbs. per foot of rope.

    .066 lbs. x 60 ft. = 3.96 lbs.

    or

    16 ounces (1 lb.) 15 feet = 1.0666 ounces per foot (1.07 oz.)

    60 feet x 1.066 oz. = 63.96 ounces 16 oz. = 3.998 lbs. (4.01 lbs.)

    3.96 lbs. (4 lbs.)

  • Calculation Examples:

    Air Weight and Weight in Water Fiber Cordage: Typical Weights

    Nylon (PA): O , 1 circ.

    Net Weight per 100 = 6.6 lbs.

    Feet per Pound = 15

    Breaking Strength = 6,650 lbs.

    60 feet of this rope weighs?

    Air Weight = 3.96 lbs. (4 lbs.)

    Water Weight (salt water) =

    3.96 lbs. x .10+ = .396 lbs.+

    .396 lbs. x 16 oz. = 6.336 ounces +

    or

    63.96 ounces x .10+ = 6.396 ounces +

    +6.336 oz.

  • Rigging a Mooring

    Mooring: Permanent ground tackle; a place where vessels (or scientific equipment) are kept at anchor.Illustrations and Definition from: Chapman/Piloting Seamanship & Small Boat Handling, 61st. Edition, Hearst Marine Books,

    New York, NY: 1994

    A typical mooring buoy is designed to

    transmit the strain through a solid rod.

    Buoys perform a useful function in

    removing much of the vertical load

    which allows the boats bow more

    freedom to lift to heavy seas.

    Mooring Buoy

    Buoy

    Length of pennant to

    chock is 2.5 times height (H).H

    Rope equals maximum

    depth of water.

    Heavy chain with swivel shackle

    up to 1.5 times depth of water.

    Mushroom anchor or

    concrete block.

    Maximum

    depth of water

  • Rigging a Mooring

    Calculation Example:

    What type of rope should you use?Most texts and manufacturers would recommend:

    A three-strand twisted nylon rope with a medium lay.

    Excellent strength to weight ratio.

    High stretch and elasticity.

    Excellent abrasion resistance.

    Size Depends on normal working loads and/or dynamic loading.

    How much rope will I need?Depends on the maximum depth of the water!

    For the purpose of this example and the ensuing calculations lets

    assume our maximum depth of our water is 32 Feet.

    In addition, lets assume we will be mooring a motorboat

    approximately 25 feet in length.