Types of Rope

Rope and cord have similar construction, but they often have different purposes and capabilities. Typically, cord will have a much smaller diameter than rope.

Rope:

• Usually thicker than 1/8-inch in diameter
• Often made from twisted or braided cords
• Stronger than cord
• Used for both functional and decorative purposes
• Types of rope range from light-duty to heavy-duty

Cord:

• Has a diameter smaller than 1/8-inch
• Made from lengths of fiber that are twisted or braided together
• Often used for lighter tasks such as crafting

The strength of a rope is rated by both its working load limit and tensile or breaking strength. The tensile strength measures the amount of tension a new rope can take before breaking.

Always choose the rope strength you need based on its working load limit not its tensile strength. The working load limit is a guideline for practical use of the rope. It tells you the maximum amount of weight the rope should support at any time. A rope's working load limit is 15 to 25 percent of its tensile strength. Never exceed a rope’s or cord’s working load limit.

• Light duty rope: Working load limit of up to 99 pounds.
• Medium duty rope: Working load limit between 100 and 999 pounds.
• Heavy duty rope: Working load limit of 1000 pounds or greater.

Consider the following when determining the working load limit you need:

• The working load limit assumes that the load is static and not moving.
• Tying a knot in the rope can reduce its working load limit by up to 50 percent.
• Abrasion resistance is needed for ropes used with pulleys, winches or other devices that cause constant wear.
• Dynamic or moving loads greatly reduce the ability of a rope to hold the load.
• Creep is the amount synthetic fibers slowly stretch while handling a continuous load. Ropes never return to their original length once creep sets in.

Safety Tip: Always consult the manufacturer’s instructions for handling heavy loads. Do not attempt to use ropes in situations in which a life will depend on them without proper training.

Rope and cord can be made from many different natural and synthetic materials. Each material has its own unique benefits.

• Polyester: Synthetic material that is UV-resistant, abrasion-resistant and maintains its strength when wet. Usually pre-stretched. Good choice for general purpose rope.
• Nylon: Synthetic material that is both flexible and strong. UV-resistant and abrasion-resistant. Weakens in water
  and does not float.
• Kevlar: Extremely strong synthetic material that is resistant to fire, extreme temperatures, stretch, water and chemicals. Has low UV resistance, so it is often covered with polyester.
• Sisal: A natural fiber used for making twine, paper, cloth, carpets and more. Sustainable and biodegradable. Low water resistance and abrasion resistance. Prone to mildew.
• Manila: A natural fiber that is very stretch-resistant and holds knots well. Sustainable and biodegradable. Like sisal, it has low water and abrasion resistance and can be prone to mildew.
• Coir: A natural fiber made from coconut husks. Sustainable and biodegradable. Used in many gardening applications.

Ropes can braided, twisted or plaited together. A rope's construction helps determine its strength and best use.

• Single braided: Also known as solid braid. Features lock-stitch construction and is well suited for use with blocks and pulleys.
• Double braided: Features braided rope wrapped around a braided core to provide extra strength.
• Hollow: Features an empty center and can be quickly and easily spliced. Ideal for anchor lines.
• Twisted: Also known as laid rope. Can be easily spliced. Most commonly used type for general applications such as tow ropes.
• Diamond braided: Features an inner core that provides additional strength or allows for filler to increase the diameter. Can be easily spliced.
• Plaited: Features four sets of strands that are intertwined together around the core.

• Some ropes come in vivid fluorescent colors for use in situations where you need to locate them quickly. These ropes are easier to find in an emergency.
• Weather-resistant ropes are treated for UV resistance, mold and mildew resistance and extreme temperatures. They can also be made from materials that naturally have these types of weather resistances.
• Abrasion-resistant ropes will hold up under activities that involve friction. These kinds of ropes are best for outdoor use, marine use and in pulleys.
• When you need rope that floats in water and maintains its strength when wet, look for those made from polyester/polypropylene. They work well for fishing and other water-related uses.