What's the Recommended Cordage Strength for Heavy Loads?

Choosing the Right Cordage

When selecting cordage for heavy loads, it’s essential to consider the material’s strength, durability, and resistance to water and abrasion. High-quality rope made from natural fibers like hemp, jute, or manila can withstand heavy loads, but it may not be as resistant to water as synthetic materials like nylon or polypropylene. For example, a 3/16-inch nylon rope has a minimum tensile strength of 12,000 pounds (5,443 kg) per strand.

Lashing Techniques for Heavy Loads

To secure heavy loads, you’ll want to use a combination of lashings and knots that distribute the weight evenly and prevent the load from shifting. A figure-eight lash is a reliable choice for securing heavy logs or timbers. To create a figure-eight lash, start by making a loop in the rope and then wrapping the working end around the post or log. Pass the working end through the loop and pull it tight to secure the load. Repeat this process several times to create a secure and reliable lash. For added strength, use a minimum of three strands of cordage per lash.

Measuring Cordage Strength

To ensure your cordage can handle heavy loads, you can perform a simple tensile strength test. Cut a length of cordage to the desired length and attach it to a fixed point, such as a tree or a post. Then, attach a known weight (such as a rock or a bag of sand) to the other end of the cordage. Slowly increase the weight until the cordage begins to stretch or fail. Record the maximum weight the cordage can handle, and use this information to choose the right cordage for your needs. A general rule of thumb is to choose cordage with a minimum tensile strength of 10-20 kg (22-44 lbs) per strand of cord.