Knots and Knotty-ness : Can you tie good knots with flat rope?

August 5, 2008 12:05 PM

So, I need some serious knots. With some serious rope, that you can buy in bulk, and that will hold up to serious weight. I've come to the conclusion that parachute cord is the way to go, and having used it in the past, I think it's great stuff. However, I want to upgrade, but there are complications: the stronger rope is flat.

This is the rope I'm interested in: 1000lb test paracord.

Will it hold less of a knot (particularly with inexperienced people tying the knots) than traditional round paracord?

Also, does anyone know of good knot tying instructions online? any that feature flat rope?

thanks!

posted by Freen to sports, hobbies, & recreation (15 comments total)

This is a compellingly vague question, for all that it has a veneer of information. What kind of "knots" are you interested in? What are you tying? Do you need something that will work as a bend?

Figure 8's are very strong and work well in flat rope.
posted by OmieWise at 12:10 PM on August 5, 2008

The single most versatile know is called a "bowline", but of course the correct knot for you depends enormously on just what you're trying to do.
posted by Class Goat at 12:52 PM on August 5, 2008

I'm with OmieWise -- we really need to know more about your intended usage to give you a decent answer. What sort of knots do you need to use, and why is this particular cord the right cord for your job?

Personally, if I needed to buy some bulk rope or cord, I'd look at either a marine supply store (e.g., some place like West Marine), or a place that sold climbing ropes and equipment, such as REI. And if I needed a rope specifically for the purpose of tying knots, I'd get a round rope of the appropriate diameter. Flat ropes and strapping are great for certain tasks, but they are generally less effective when knotted. If I absolutely HAD to use a flat rope, I'd be sure to use the water knot, which is a great knot for flat ropes and straps.
posted by mosk at 12:55 PM on August 5, 2008 [2 favorites]

I have used flat cord and I was able to tie clove hitches and bowlines with it without much problem. I found it could be stored more compactly than the equivalent round rope, too.
posted by tommasz at 1:05 PM on August 5, 2008

Webbing is used quite a lot in climbing, so yes, you can tie good knots in it. Here is a great animated how-to for the water knot that mosk mentioned.
posted by misterbrandt at 1:06 PM on August 5, 2008

For about 2.5 times the price, EMS will sell you very colorful 5mm round accessory cord rated at 1134 lbs.
posted by jamjam at 1:51 PM on August 5, 2008

REI also has round 5mm cord rated for ~1,200 lbs for 25c per foot.

What are you planning to use the rope for? I wouldn't climb or rappel on anything rated for 1,000 lbs...
posted by foodgeek at 2:12 PM on August 5, 2008

This is an amazing website about knots.
posted by salvia at 2:16 PM on August 5, 2008 [2 favorites]

I think you are working backwards by choosing the rope first.

Instead, start with the question of what you need to do with the rope, and then choose the rope based on that, and then lastly you can choose an appropriate knot for the rope and for the situation.

If you are suspending people, or heavy things above people's heads, then that paracord is not the right choice. If you are tying up people (like, you know, in bed), you will want to choose rope with a really nice "feel," and it's ultimate strength is not so important (again, presuming no one is being suspended) though thicker rope tends to feel better and not cause rope burn.

Depending on what you are doing, you will either want more stretchy rope, or less stretchy rope; water absorbency and resistance to abrasion are also sometimes critically important.

So yeah, not enough information here to answer the question.
posted by Forktine at 3:31 PM on August 5, 2008

Zomg 100 knot club eagle scout in the heeeeezy. (No, for real.)

What are you tying, and why are you using flat stuff? Are you going to shock load it? What, praytell, are you going to DO with 1000lb rated paracord that won't involve cutting off some part of your body?
posted by TomMelee at 5:00 PM on August 5, 2008

Yeah, seriously, tell us what you're wanting to do with the rope (other than just tie knots) and we can then make a recommendation.
posted by spikeleemajortomdickandharryconnickjrmints at 5:17 PM on August 5, 2008

I'm going to be using it as guy wire for a 25 foot tower. We're going to be tying this down to rebar stakes in ground. We typically use bowlines to attach to the top of the tower, and clove hitches to tie down to the rebar, with 550lb test parachute cord. We also use the parachute cord for all sorts of other stuff as well.

We've use parachute cord in the past, and it has performed quite well. Looking at the options, though, I think I'm going to go with this rope and get 500 feet or so for heavy duty use, and another 500 feet of regular 550lb test parachute cord for everything else.

Thanks!
posted by Freen at 8:17 AM on August 6, 2008

...the stronger rope is flat...Will it hold less of a knot (particularly with inexperienced people tying the knots) than traditional round paracord?

Answering just this bit in the clearest way: Yes, knots behave differently in flat cord versus round cord. Good instructional material on knots will call out knots that work well in flat cord for various purposes.
posted by madmethods at 8:21 AM on August 6, 2008

I'm going to be using it as guy wire for a 25 foot tower. We're going to be tying this down to rebar stakes in ground. We typically use bowlines to attach to the top of the tower, and clove hitches to tie down to the rebar, with 550lb test parachute cord. We also use the parachute cord for all sorts of other stuff as well.

I don't know how heavy your towers are (or if they have people up on them, etc), how high the winds are, and so on.

But please be aware that even appropriate and well-tied knots reduce rope strength by about 50%; less well-tied and less-appropriate knots reduce the breaking strength even more. (Here is another chart of knot strengths; there are many others easily available. These are only for correctly-tied knots; the reason you don't see the bowline often used in climbing anymore is that it is easy to tie incorrectly, but looks about the same tied well or poorly; the figure-8 is easy to tie and easy to visually assess for safety. Whatever knots you choose, learn to check and recheck them.)

So when you are figuring out your safety margins, please be realistic about worst-case scenarios. Particularly with things above your head (25' towers count) and inexperienced helpers, you want those safety margins to be really robust. That rope might start looking pretty inadequate when you take some real-world factors into consideration.

Please have someone who really knows rigging and overhead safety to check out what you are proposing; there may be some easy improvements that could prevent a really nasty accident.
posted by Forktine at 8:59 AM on August 6, 2008

Rope? As guy wire? You know it stretches, right?
posted by TomMelee at 11:03 AM on August 6, 2008