Shroud lines?

[1shot]

I've been searching for info and discussion on shroud lines on hammocks here and on the web without luck so I thought I'd start a thread.

First of all, I'm not even sure they are called shroud lines. I'm talking about the lines that go between the hammock fabric and the suspension lines. My old hammock has 10 double lines on each end about 18" long. I wonder if these are called something else and the reason I can't find info on them is because I'm searching the wrong term. If so could someone please point me in the right direction.

I'm considering making my own DIY design for my second hammock (first DIY) and have been wondering about using shroud lines. A little background, I'm new to hanging (I've had a hammock for many years that I used for occasional lounging around camp but have yet to spend a night in a hammock), but I've done plenty of gear making and modifying usually with good results. Shroud lines don't seam to be all that popular here so I was wondering why? What are the plusses and minuses? How would I determine the needed working load of these lines?

The way I see it the pluses would be
• less critical tarp coverage at the ends as any water would just pass through or be handled by drip lines.
• It would make the material effectively longer than what you have.
• Lines could be adjusted individually to effect the lay.
• Could decrease weight

And, minuses
• easily tangled.
• significantly more difficult to attach and possible weak spots at joints.
• could increase weight.

I simply have no idea on the weight issue although I suspect it would be just slightly heavier. Another question, how many lines would actually be under load? When sitting on my hammock it seams that as few as 6-8 pairs are loaded, and some less than others. When lying most of the lines bear some load but the ones supporting my feet are far less so. I'm really hoping some of you scientists and mathematicians [edit(as well as anyone else)]out there will have some good info for me. Thanks so much for your help!

[WV]

Go for it. Your assessment of pluses and minuses is pretty sharp. My experiences suggest that overall weight would be reduced, but I've used Spectra kite lines which are very strong for their weight. Adjusting lines can produce a very comfortable hammock. Construction time is huge, if you do it the way I do (individual tiny whoopee slings for adjustment), but I recently acquired an Exped Scout hammock. It uses one continuous cord on each end going back and forth to the suspension line from the hammock end. If you substitute bungee for the last 3 or 4 cords on one end, you get something that approximates the side-stretch Knotty described.

All of the plus and minus factors you cited are right on the money. Be encouraged and cautioned, respectively. Your observation about the variations in load on individual lines is also correct.

Lately I've been calling them shroud lines, too.

[1shot]

Go for it. Your assessment of pluses and minuses is pretty sharp. My experiences suggest that overall weight would be reduced, but I've used Spectra kite lines which are very strong for their weight. Adjusting lines can produce a very comfortable hammock. Construction time is huge, if you do it the way I do (individual tiny whoopee slings for adjustment), but I recently acquired an Exped Scout hammock. It uses one continuous cord on each end going back and forth to the suspension line from the hammock end. If you substitute bungee for the last 3 or 4 cords on one end, you get something that approximates the side-stretch Knotty described.

All of the plus and minus factors you cited are right on the money. Be encouraged and cautioned, respectively. Your observation about the variations in load on individual lines is also correct.

Lately I've been calling them shroud lines, too.

Thank you WV, I was hoping you would chime in. I got the term shroud lines from your thread on your insulated cuben little grey cloud. I suppose the term came from parachutes? Kites? What weight kite lines are you using? How many per side? I had considered using 'mini whoopies' but quickly disregarded the idea considering the difficulty. Props to you for doing it. Do you have a way to lock them off once you find the sweet spot?

On my hammock the lines are fed via button holes through about 2" of channel, with another couple inches w/o lines between them. Seams like there should be a better way. How do you do yours?

Thanks.

[JohnSawyer]

The only CON I would add is: (maybe) about bugnet coverage issues... might add weight over 1.1oz fabric...

My first hammock had shroud lines... still use it in the back yard... Though on the water issue: wicking would be a problem...

For that matter, there's a recent thread on a gathered end spreader that might work... takes shroud lines down to 2 per end, and uses a dowel or short length of PVC.

I'll have to find it... This might be a way to shorten the body of the hammock without losing comfort and strength...

[1shot]

Thanks John. Hadn't thought of wicking. I followed that thread on the mini spreader and have something similar in my current design because of it (although the "design" is just in my head at this point). I don't know at this point what I am going to do as far as a bug net. The high pitched buzz of mosquitos drives me into a murderous rage and often leads to breaking things if it's to close to my ears and too constant. So I'm thinking up draping it from the edge of my tarp to the ground. Of course this would be quite heavy so really I have no idea what I'm going to do. But baring that I think it would just be sewn to the edge of the hammock fabric and avoid the shroud lines altogether. Some good things to think about going foreward with nailing down the design specifics. Thanks.

[1shot]

Still not sure how strong those lines need to be. Does anyone have a formula, rule of thumb or, even just an opinion on it. Maybe I'll play around in my hammock and see what the least amount of lines I could load is (I need Shug to do a headstand in it I guess,JK). Then just come up with a safety factor x my weight and divide by the number of lines I come up with. I'll post what I come up with.

[JohnSawyer]

At a perfect 30 degree hang, the force on the suspension is roughly your body weight on each side... since the shroud lines don't take the load evenly, I would suggest each line be rated for 1/2 your weight or more... since the lines will weaken over time, it's better to be safe... my byer of Maine hammock lines are frighteningly small, though... I guess it matters how many lines you have, too...

As I think about it, having a line with some stretch might be beneficial as the load will then distribute automatically. Mason's line would work if you had enough but paracord it zing-it would be stronger... since paracord and mason's line are so cheap, maybe that would be a good prototype material...

[1shot]

I figured the minimum lines i can load to be three per side and they all tone the same pitch with a pluck so they're probably close to the same amount of load. Ok, so I'm 155 x safety factor 5 = 775. My lines are hanging at about 30*. If my math is not wrong(likely is) the lines see 2x the weight, so 1550lbs/6 = ~260lbs. Not sure a safety factor of 5 is necessarily needed here though as if one line snaps the others will provide significant redundancy.
SF4 = 207
SF3 = 155
Also, the foot end lines will never see anywhere near the loads. Of the entry/body side so those could be smaller.

My current design is an asymmetric where only one side will ever be the entry/body side.

Any thoughts?

[1shot]

At a perfect 30 degree hang, the force on the suspension is roughly your body weight on each side... since the shroud lines don't take the load evenly, I would suggest each line be rated for 1/2 your weight or more... since the lines will weaken over time, it's better to be safe... my byer of Maine hammock lines are frighteningly small, though... I guess it matters how many lines you have, too...

As I think about it, having a line with some stretch might be beneficial as the load will then distribute automatically. Mason's line would work if you had enough but paracord it zing-it would be stronger... since paracord and mason's line are so cheap, maybe that would be a good prototype material...

Some good points again John, thanks. Now off I go to figure out what masons line and zing-it are.

[WV]

My winter hammock has 20 shroud lines on each end. They are 130 lb. test Spectra kite lines. They have withstood 3 years of service. Newer hammocks have 17 lines on each end (spaced 3" apart), and I've used 150 lb. test Spectra. I've also used 150 lb. dacron lines to save money. When you space lines more than 3 " apart, the strain on the fabric at the attachment point becomes more of a concern. I usually make a channel on the end and reinforce it with a 2" strip of pack cloth, then run a piece of amsteel, dynaglide, or utility cord through the channel. The shroud line attachments go through holes melted in the channel with a soldering iron (melted nylon = instant grommet). They're larks-headed around the heavier cord in the channel. No failures yet.