Monday, February 4, 2013
Learning about rope and cordage types
There is no doubt of the usefulness of rope and cordage. Rope can be used to tie a clothesline in the backyard, used to haul food out of the reach of critters, set traps, or even tie your kids up in a closet when they misbehave (don’t do this please-it would be funny, but you would probably go to jail. Not cool).
So with all the different uses out there, it should come as no surprise that there are many different kinds of rope, and it can be confusing. I am going to try and give everyone a little ropeducation (it’s the best I could come up with. Sorry, it’s embarrassing).
Let’s start with the two basic rope material categories: natural and synthetic. The vast majority of rope today is synthetic. Synthetic rope is made up of man-made, engineered material. These are your nylons, polypropylenes, polyesters, and others. There are MANY different types of man-made rope materials. Some are better than others. For example, Nylon is one of the strongest synthetic ropes, but loses some of its strength when wet. Polypropylene is cheap and relatively strong, but is prone to break down in UV rays. Polyester has much less stretch than nylon, just as strong, and more durable. But polyester is more expensive. The picture at the top of this post is of a climber carrying synthetic rope.
There second rope material is natural rope. Natural is anything you find in nature which can be used as rope or cordage. Synthetic rope is better than natural rope in almost all situations. It is heavier, weaker, and bulkier. Natural rope that you can purchase at a store is generally some variation of hemp rope. Above is an example of hemp rope. Notice the frays of hemp that make up the rope.
Now that we have that out of the way, let’s talk about rope construction. Rope is made by taking small strands of a fiber and twisting them together in a pattern to create a larger, stronger strand. There are a few different construction types: twisted, braided, and kernmantle.
Twisted rope is exactly how it sounds: individual fibers twisted together, forming a rope with a twisted look. Twisted rope is the weakest and cheapest type of rope construction.
The next step up in strength is braided rope. Rope can be single or double braided. Single braid consists of individual strings braided together, much like hair is braided. Double braided is basically a braid inside of another braid.
The strongest and most abrasion resistant material is kernmantle. Kernmantle rope consists of an inner core and and outer sheath. The core is generally twisted together, and the outer shell is braided. This is what you see in climbing ropes and other high demand applications. It is naturally one of the most expensive rope types.
So with all the different types of rope, what do you need? Your rope selection will depend primarily on the application. After all, some of us (climbers, military, law enforcement, firefighters) use rope to save lives. Others use rope to protect expensive investments (it would be a shame to see your yacht playing bumper boats with others in the marina because you used sub-par rope). See part two of my rope and cordage series: Selecting the right type of rope.