Types of Rope

The strength of a rope is rated by its working load limit and tensile strength (also called breaking strength). The tensile strength is determined in a lab and measures the amount of tension a new rope can take before breaking. The working load limit is a guideline for practical use of the rope. The working load limit tells you the maximum amount of weight the rope should support at any time.  

Although the working load limit is only 15  to 25 percent of its tensile strength, always determine the strength you need by working load limit and not 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. 

Keep these factors in mind 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.  

Some ask, what is rope made out of? 

• Rope and cord can be made from many different natural and synthetic materials. These materials are either braided, twisted or plaited together. 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. 
• Polypropylene: Lightweight synthetic material that is resistant to mold, mildew and many chemicals. Floats in water. Has low resistance to UV rays and abrasion.  
• 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. 

Rope Construction: 

• Rope construction helps determine its strength and best use. Below are the common types of rope braids and constructions: 

• 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 water ski tows and anchor lines. 
• Twisted: Also known as laid rope. Can be easily spliced. Most commonly used type for general applications such as tow ropes and dock lines. 
• 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. 

• Color: Some ropes come in vivid fluorescent colors for use in situations where you need to know where it is at all times. These ropes are easier to locate in an emergency.  
• Treatments: When using ropes near or in water, look for types of rope that are treated to repel water and protect against mold and mildew.  
• Weather-resistant: Weather-resistant ropes are treated for UV resistance, mold and mildew resistance and extreme temperature resistance. Alternatively, they are made from materials that naturally have these resistances. 
• Abrasion-resistant: Abrasion-resistant ropes will hold up with outdoor use, marine use and pulleys. 
• Polyester/Polypropylene Combination: Ropes made from this combination of materials are best suited for marine applications, fishing and other water-related tasks. Look for this combination when you need rope that floats in water and maintains its strength when wet.