Rope

Rope
 
Rope is a versatile item that can come in handy for any number of tasks. From lifting objects with blocks and pulleys to securing items in your truck bed, rope serves many useful purposes. With a large variety of types to choose from, including nylon, manila, sisal and more, it’s important to select a rope that’s designed to handle the stresses you’ll be putting it through. Manila rope, for example, withstands the effects of sunlight very well, making it ideal for outdoor use. Ropes are also available in a number of different configurations ranging from hollow to double braided. Consider the following questions to help determine which types of rope are best suited for the tasks you frequently undertake:
 
        • What types of rope are available?
        • What types of cord are available?
        • In what ways can rope be constructed?
        • What characteristics are important to you?
        • Are there any special features you’d like to have?
 

Rope, Cord, Characteristics and Construction


The primary reason it’s important to choose a rope that has the strength and durability to handle the jobs you plan to use it for is safety. Ropes are often used to hold objects in place and to lift or tow heavy items, so if one snaps it can create hazardous conditions or cause considerable damage. To help ensure safety, it’s important to properly care for and store ropes. Never attempt to use a rope that’s worn or frayed in any way. Heat in excess of 140°F can damage many ropes whether they’re in use or not, so avoid storing them or using them in any situation where they’ll be exposed to extreme heat. Keep rope clean and store it in a dry place with good circulation to prevent mold or mildew from rotting it. Avoid kinking, and bear in mind that knots greatly reduce the strength of rope because they cause stress to be focused on a single point rather than spread out along the entire length of the rope.
 
Rope and Cord: The primary difference between rope and cord is thickness. Rope is a length of flexible material that’s usually thicker than 1/8" in diameter. Cord, on the other hand, generally has a diameter smaller than 1/8". Cord is often used for lighter tasks such as opening a curtain, stringing a clothesline or tying together bundles of twigs. Rope, on the other hand, is used for a variety of tasks ranging from light tying to heavy-duty towing, depending on the material it’s made from, its thickness and its characteristics. The chart below describes some of the more commonly used types of cord and rope as well as a few points of consideration for each.
 

Type Material

Description

Points to consider

  CORD  
Clothesline Cord May be braided with a cotton or polyester filler or may be made of wire encased by a vinyl sheath. • Possesses great strength to
   handle the weight of wet
   fabrics
• Must be anchored to support
  structures 
Cotton A soft and pliable natural fiber. • Ideal for use in pull cords on
  blinds and sashes
Twine Lightweight cord that consists of one-twist plies and may be made from different materials including jute, sisal and polypropylene. • Natural fibers have a woolly
  surface that makes them easy
  to tie
• Polypropylene provides
  greater strength
• Ideal for lightweight
  applications
  ROPE  
Manila Rope A heavy natural fiber made from hemp that’s available in diameters ranging from 1/4" to 3/4". • Ties easily and remains
  secure
• Resists damage from sunlight
  and won’t melt
• Strong
• Store somewhere dry to avoid
   rope becoming damp
• Ages well
Nylon Rope A synthetic fiber that’s very elastic and may be braided or twisted. • Strong and flexible
• Use a flame to melt ends
  when cutting to prevent
  unraveling
• Provides abrasion resistance
• Doesn't rot
• Resistant to many chemicals
• Ages well
• Absorbs shock
Polypropylene Rope A lightweight, waterproof synthetic fiber that can float in water. • Ideal for marine applications
• Strong
• Somewhat difficult to tie
• Use a flame to melt ends
  when cutting to prevent
  unraveling
• Ages well
Polyester A synthetic fiber that provides less elasticity than nylon but is otherwise similar. • Ages well
• Provides abrasion resistance
• Resistant to rot and mildew
• Resistant to ultraviolet light
Polyethylene  A synthetic fiber similar to polypropylene but somewhat heavier. • Not as strong as
  polypropylene
• Provides abrasion resistance
Sisal Rope A natural fiber that holds knots well. • Lower Strength
• Best for light-duty or
  temporary applications

 
Characteristics: All rope is defined by certain characteristics. It’s important to know what various terms mean and how they affect usage to determine whether or not a rope is suited for the task at hand. The strength of a rope determines how heavy of a load it can handle. Safety factor and breaking strength are other important considerations. Safety factor is a measure of the load a rope should be rated to handle a given project while breaking strength is the amount of weight a rope can bear without breaking. For light applications, a safety factor of 5 will generally suffice. This would mean that if you plan to use the rope to support a 10 lb. object, you’d want to purchase one with a breaking strength of at least 50 lbs. Moderate and heavy-duty applications may require a safety factor of 12 or more. Always consult the manufacturer’s instructions for handling heavy loads, and do not attempt to use ropes in situations in which a life will depend on them without proper training.
 
        • Abrasion resistance is key for ropes that will be used in conjunction with pulleys, winches or other devices 
          that cause constant wear
        • Flexibility determines how easy a rope is to manipulate under various conditions
        • The load a rope is rated to handle assumes the load is static, or not moving
        • Dynamic, or moving, loads greatly reduce the ability of a rope to hold the load, and as a result, safety 
          factor must be significantly increased
        • Right-laid rope is twisted to the right around the core while left-laid rope is twisted to the left
        • Creep is the amount by which synthetic fibers slowly stretch over periods of being subjected to a 
          continuous load
        • Ropes do not return to their original length once they have begun to creep
 
Construction: Rope can be constructed in various ways, with the most common configurations including single braided, double braided, hollow, twisted, diamond braid and plaited. Single-braided rope, also known as solid braid, features lock-stitch construction and is well suited for use with blocks and pulleys. Double-braided ropes feature a braided rope wrapped around a braided core to provide extra strength. Generally made with three-strand construction, twisted rope is perhaps the most commonly used type for general applications, such as tow ropes, dock lines and more. Plaited ropes feature four sets of strands that are intertwined together around the core.
 
        • Ropes are available with multiple strands, with 3, 4, 8, 12 or 16 being common
        • Hollow-braid ropes feature an empty center and can be quickly and easily spliced
        • Hollow-braid ropes are ideal for water ski tows, anchor lines and more
        • Diamond-braid construction features an inner core that provides additional strength or allows for filler to 
          increase the diameter and can be easily spliced
        • Twisted rope is also called “laid” rope and can also be easily spliced
        • Splicing joins ropes together much more securely than knotting
 

Features


Color: While most rope is naturally colored, some ropes have vivid fluorescent colors, which are ideal for use in situations where it’s important to know where the rope is at all times. You’re less likely to trip over a highly visible rope, and it’s easier to locate in an emergency situation.
 
Treatments: If you’re planning to use a rope for marine applications, such as tying up a jet ski to a dock or keeping objects in place on your boat, look for one that’s treated to repel water, which will help prevent it from swelling and becoming stiff when it dries. You’ll also want treatments that protect against mold and mildew, as damp ropes can quickly become infected with both, which will render them useless.
 
Polyester/Propylene Combination: Ropes with this construction are ideally suited for marine applications, fishing and other water-related tasks.