Do you think Paracord is suitable (strong enough, durable, abrasion resistant etc) to string up a hammock? I weigh about 150 lbs. Thanks.

If you use true parachute line or cord commonly refered to as 550 cord there schould be no problem, But I would double it anyway. That way you don't have to cut up small lenghts and you can reuse it latter.

certainly, learn your knots first though,( and doubling the rope won't hurt anything).

I've fallen asleep in a hammock hung by 550 cord, woke up still above the ground. (Regretfully, I'm a little more than the 150 target weight you have in mind... so that's good news, you have an extra margin of safety!)

Both ends were doubled, and went to straps that go around the tree. This was real 550 cord. There are plenty of cheap imitations that I wouldn't want to use to support a human... Also, the static capacity wouldn't be an issue, with even one line, but, the shock capacity if you, ah, dropped into the hammock might be an issue, especially if you had any abrasion. The straps around the tree seem to help.

Ya, i do it all the time! I just double it (I go around two times)

-jace

Negative. Big, cussing, dripping, stinking negative.

I used to use paracord for this. Then one night, I set up in swamp. About three in the morning, the 550 line snapped at a knot, and dumped me and my hammock and my polypro into the swamp. Needless to say I was cussing, dripping, stinking and very negative about that.

Knots kill strength, and it is cumulative. Square knot costs you about half the strength of a line, most others do the same or worse. So two knots in a length of 550 cord turns it into 175-ish cord! Try 1" or wider nylon webbing- that has a rating of at least 4000 pounds (two tons). If that breaks, you either have annoyed some gremlin, you've got a fun hammock, or you are a REALLY big guy.

Better, have an industrial stitcher (an upholstery shop can usually do this) sew loops into the ends. Or just use a tow strap. Actually, you need two. Wrap them around the trees several time. Use climbing 'biners to clip the ends and the hanging loops on your hammock together.

But, how do you get around putting a bend in the paracord? It seems to me that no matter what one does, in order to attach the paracord to almost anything, there must be a 90 degree or greater bend, with subsequent loss of strength? No?

Exactly. That is why you don't use it to hold yourself up.

You have the same problem with webbing. But, half of 4000 pounds is still a ton. Half it again, and a third time, and it is still 500 pounds, and if that won't keep you off the ground you've got a bigger problem. And that is for the weaker end of 1" webbing, you can get a LOT stronger if you go up in grade and width.

Tubular webbing tied with a tape knot is one of the strongest ways to go...by far better stronger than any reasonably sized rope with a knot in it.

And don't forget there are creative ways to get around putting too many load bearing 'bends' into a rope.

Here's an interesting bit of web information about failure testing done by a search and rescue team:

http://www.xmission.com/~tmoyer/testing/pull_tests_11_98.html

It breaks on me from time to time, I weigh about 220 lbs clothed.

I use what is called mule tape, it is 0.5 inch flat webbing reated at 1800lbs even if a knot cuts that to half then it is still 900lb breaking strength. I usually use a bowline to tie off to the tree with the mule tape double reapped around the tree. Also the flat tape will not slip like a rope does.
cheers

This related to a classic problem in rigging for cranes.

In theory 'para-cord', 550, certainly has enough tensile strength if it was just a question of suspending a single person's weight hanging from two lines. Even given a loss of around 15% for the line being wet and another loss of 25% or so for wear and tear.

But before you go diving into your hammock feeling you are safe there is another issue: geometry.

And here you were thinking that you would never need geometry. LOL.

Lets for a second assume your hammock was instead a stiff board. And lets assume the points of attachments were directly above the ends of the board. You sit your round 250 pound rump down on the center of the board. Each vertical line takes half of this. Each is under 125# of pull.

Things get more complicated as the lines move away from vertical.

Rigged 60 degrees from vertical you looking at each line taking 1.15 times half the total weight. 125# * 1.15 = 144#

At 45 degrees the multiplier is 1.414 so 125# * 1.414 = 176#

At 30 degrees, about where most people tend to rig their hammocks, the multiplier is 2.0. Or 125# * 2.0 = 250#

At 5 degrees the each line is looking at 11.47 times half the total weight. 11.47 * 125# = 1433.75#

The 'flatter' the hammock the more stain is put on the lines. Obviously somewhere between 30 degrees and 5 degrees your going to run into a problem. Para-cord is strong stuff but most of 3/4 of a ton is way too much to expect. Even more so that it loses strength when wet, old and slightly worn.

The obvious answer is to double or triple the para-cord to get a significant safety factor for how your rigging you hammock. The tighter you rig the hammock the sturdier the rigging will need to be.

Don't count out using para-cord. It is good stuff. Triple or quadruple the line and you could pretty much tow a car. Even the heaviest rope is made out of very thin threads.

Wouldn’t the best option be to construct the hammock like a standard hammock in constructed? They use regular rope that probably isn’t much unlike 550-pound parachute cord. What they do is take the multiple lines that are woven together to form the net section and join them up and braid them on either end. Combining multiple lines together in a good braid will multiply the strength of the line considerably (quite a bit more than just by the number of lines, if I recall correctly).