rope and trees
- Thread starter Steve M
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Hey Guest, Early bird pricing on the Summer Moot (29th July - 10th August) available until April 6th, we'd love you to come. PLEASE CLICK HERE to early bird price and get more information.
I found an 18mm tubular polyester webbing option which looks like it has a 9.8kN (1000kg) static strain: http://walkhigh.co.uk/acatalog/Cord_and_Tape.html
However, this is quite over-rated for tarp requirements. I re-did oetzi's calculations from scratch: For a 100kg load, as long as the hammock tapes are at least 20° to the horizontal you have a maximum static strain of about 1.5kN. I reckon a good, flat (non-tubular), lightweight, 20mm polyester webbing rated at 5kN would be a good option. That gives a 3x safety margin.
However, this is quite over-rated for tarp requirements. I re-did oetzi's calculations from scratch: For a 100kg load, as long as the hammock tapes are at least 20° to the horizontal you have a maximum static strain of about 1.5kN. I reckon a good, flat (non-tubular), lightweight, 20mm polyester webbing rated at 5kN would be a good option. That gives a 3x safety margin.
A useful comparison of polypropylene and polyester properties: http://www.haywoodproducts.com/webbingstrapping
Note that nylon stretches when wet, so not really an option IMO. Bizarrely though, the tapes supplied with my Nomad Tropical hammock are, indeed, (0.5" tubular) nylon.
Note that nylon stretches when wet, so not really an option IMO. Bizarrely though, the tapes supplied with my Nomad Tropical hammock are, indeed, (0.5" tubular) nylon.
I've been in contact with the Finnish company in the link. They sell 20mm and 25mm polyester webbing that's only 18g and 24g per metre respectively. The 25mm is rated at 5.2kN. The 20mm isn't rated, but I can do the maths and reckon that 4kN will be more than adequate for hammock tapes.
Black 20mm and 25mm is in stock, but they only have 25mm in olive green. 20mm olive green (which is ideally what I want) is due in within a month.
Is anyone interested in joining me in a purchase to save on postage costs? If there is enough demand, it's cheaper to buy rolls of the material rather than by the metre.
As for the damage to the trees:
Obviouly open wounds to the tree is considered a damage, what people tend to forget is that crushing the layer directly underneath the barch is equally as damagaing as making an open wound.
Consider a tree's "infrastructure" like a bundle of straws (you know. straws for drinking)
It is only the outer layer that is alive on a tree. This would then be a single layer of very thin straws.
If you crush or cut open part of this layer, the tree's response is to fill the underlying straws with toxins in the full length of those straws (basically a natural very strong fungicide) to prevent any infections developing, thus cutting of the damaged parts.
The living layer will then start to grow over the damaged parts, nomatter if those parts are open or still under the barch.
No question about it. Line bad, tape better.
EVen better is if you take some decent padding material with you. Could be a coffebean sack for each tying thats under strain.
Obviouly open wounds to the tree is considered a damage, what people tend to forget is that crushing the layer directly underneath the barch is equally as damagaing as making an open wound.
Consider a tree's "infrastructure" like a bundle of straws (you know. straws for drinking)
It is only the outer layer that is alive on a tree. This would then be a single layer of very thin straws.
If you crush or cut open part of this layer, the tree's response is to fill the underlying straws with toxins in the full length of those straws (basically a natural very strong fungicide) to prevent any infections developing, thus cutting of the damaged parts.
The living layer will then start to grow over the damaged parts, nomatter if those parts are open or still under the barch.
No question about it. Line bad, tape better.
EVen better is if you take some decent padding material with you. Could be a coffebean sack for each tying thats under strain.
Shambling Shaman
Bushcrafter (boy, I've got a lot to say!)
I have some "tree hugger's I can send you if you want? so you can see how HH do the stitching etc.
Thanks for the offer, but I'm not planning on doing any stitching! I've seen the Ray Mears Eco Sleep System DVD and I've got a fair idea of how I want to set up my hammock.
Cheers,
Joel
I have started a group buy for lightweight polyester webbing: http://www.bushcraftuk.com/forum/showthread.php?t=41502
