Self tensioning guylines...WHY?

**SouthernExposure** · 01-13-2013, 10:38

Originally Posted by fallkniven

Now I use 1/8" doubled over if I remember correctly, and wrap the cord around it in a spiral to keep it neat. (I know I know, a piece of 1/8" doubled over is the same as a 1/4", but it wasn't even close in regards to tension strength.)

Your doubled over 1/8" shock cords certainly give you more tension, but it is only about half of what you get with (1) 1/4" cord based on comparing cross-sections.

Let's go to the chalkboard. (2) 1/8" shock cords have a combined cross-section (pi x radius squared) of .0245 square inches. (1) 1/4" shock cord has a cross-section of .049 square inches. To approximate the same cross sectional area of elastic between the two diameters, you would need (4) 1/8" shock cords.

I hope this helps once you wipe all of the geek off of it.

SouthernExposure

**Mr. Tettnanger** · 01-13-2013, 10:45

I broke down and ordered 100FT of 1/8 shock cord from Supply Captain.

I am not into Gadgetry, but I may make up a few and test them out.

Thanks for the replies!

**fallkniven** · 01-13-2013, 10:58

Originally Posted by SouthernExposure

Your doubled over 1/8" shock cords certainly give you more tension, but it is only about half of what you get with (1) 1/4" cord based on comparing cross-sections.

Let's go to the chalkboard. (2) 1/8" shock cords have a combined cross-section (pi x radius squared) of .0245 square inches. (1) 1/4" shock cord has a cross-section of .049 square inches. To approximate the same cross sectional area of elastic between the two diameters, you would need (4) 1/8" shock cords.

I hope this helps once you wipe all of the geek off of it.

SouthernExposure

I understand why, but when I typed it out, I thought I might get a "...but it's the same thing, no?" Cool see the math for it though.

**Bubba** · 01-13-2013, 10:59

Originally Posted by Mr. Tettnanger

I broke down and ordered 100FT of 1/8 shock cord from Supply Captain.

I am not into Gadgetry, but I may make up a few and test them out.

Thanks for the replies!

Actually I and many people use long lengths of shock cord for the side panel pulls.

**Mr. Tettnanger** · 01-13-2013, 11:04

Originally Posted by Bubba

Actually I and many people use long lengths of shock cord for the side panel pulls.

I was thinking about that. I may use it for the door tieouts as well.

How do you connect/set that up?

**OneThing** · 01-13-2013, 11:15

I have a Hennessy Hammock. It came with a rain fly that will just cover the hammock. There is little room for error. On the AT in 2004, eating dinner under the tarp, rain filled my hammock, with my sleeping bag & dry clothes in it.

There are only two tie outs on this fly. I've reinforced the tie outs, and use 1/4 shock cord. I wish I would have known this trick in 2004 & 2005, it would have saved me from some wet nights in big storms, & getting in & out of my hammock.

For me, there is no fiddle factor at all. The few grams of added weight for safety and added convenience is well worth it.

**OutandBack** · 01-13-2013, 11:22

Back when I started hammocking I tried shockcord tensioners. 2-1/8" and found I could never get the tension I wanted on the tarp unless I stretched the shockcord to its limit
which kind of defeats the design. I have since gone back to straight tie-outs.
YMMV

**stalker42** · 01-13-2013, 19:37

Why would you not simply at a loop of shock cord to the tie outs then tie the guy line to that? Seems it would do the same thing and be easier to set up.

**clean** · 01-13-2013, 19:39

I believe the problem there is if the shockcord breaks.

**Bubba** · 01-13-2013, 19:59

Originally Posted by Mr. Tettnanger

I was thinking about that. I may use it for the door tieouts as well.

How do you connect/set that up?

I have about 8 feet of shock on each side of my tarp. I actually tied each end of the shock cord to each of the panel pulls in effect creating a "V" with the top of the "V" being the two panel pulls. I larkshead about 8 feet of line that either goes to the ground or to a nearby tree or branch. I can slide the line along the shock cord in case the natural anchor point is not exactly in the middle of the tarp. To get a horizontal pull on the "V" when there are no nearby trees, I can put a trekking pole or branch at the bottom of the "V" where the shock cord and line meet and then secure the line to the ground which creates a "Y". Because the there is pull from 3 directions, the trekking pole which is at the centre of the "Y"is pretty stable.

For my doors I have about 2 and a half feet per door. Its a good length to secure to the opposite corner to keep the doors closed or I stake them at the base of the tree to have the doors partially opened. If I want to stake or tie them out further, I just grab some spare line I always carry.