Tarp and Hammock Tutorial

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FreddyFish

Settler
Mar 2, 2009
565
2
Frome, Somerset, UK
FYI, this maybe of interest to fellow Hammock-ers. :hammock:

Can't remember where I found it but it explains the different forces involved on the rope/tapes and the trees, depending on the load (how fat you are) and the strength of the ropes/tapes you use to attach to the trees. In relation to the angle you like to hang your hammock.
The most interesting section is 'the tensile force on ropes'
It looks like if you want to get close to the rated value of your tapes/ropes you need to have an angle of 30 deg... :confused: That don't sound to comfy for sleeping.
But non of this makes any allowance that when you tie knots in your tapes/ropes this drastically reduces the tensile strength, quite often by a factor of 60%.


hammockphysics_original_original.jpg


So bottom line, make sure you don't use 550 paracord tied together and try to sleep as flat as possible unless you weight about 4.5 stone. Cos' your bottom will end up on the floor... :stretcher:
(I know people will have lots of stories about putting a family size car in a hammock with only a bit of paracord... but I'm only sharing the maths so don't shoot the messenger :D)
 

FreddyFish

Settler
Mar 2, 2009
565
2
Frome, Somerset, UK
Those numbers seem to be wrong (Yes, I'm the sort of person who checks them).

LMAO...

I be disappointed if we didn't have someone here that would check.

Don't forget I did say that I had just come across this and was just sharing the find.

So is all a load of pony???
Is the theory sound?

Do enlighten us.
 

armie

Life Member
Jul 10, 2009
266
7
61
The Netherlands
So is all a load of pony???
Is the theory sound?

Do enlighten us.

The theory is sound, the formulas are correct. It's just that the numbers in the table are not as accurate as the two decimals suggest.
Example with two decimals accuracy:
For a weight of 250 lbs and an angle of 5 degrees, the tensile force should be 1434.21 lbs and not 1434.48 lbs, a shocking difference of 0.27 lbs!

Edit: also, the 200 lbs 5 degrees example (above the S vector) is wrong - about 100 lbs off.
 
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Greenbeast

Tenderfoot
Sep 21, 2009
92
0
Northiam, East Sussex
On saturday night 'in the field' I managed to remember the two main knots from a couple of reads through and one practice in the garden at home.

So i could probably get away without printing it now, but if you've sent it i will take a look and see what i can do still
 

Paul3103

Member
Dec 30, 2009
24
0
East Yorkshire
Thanks for the tutorial, it will help a lot when I go away next month.

I am also removing the plastic adjusters fom my tent as I no longer need them thanks to your advice.

Should save myself a few grams?
 

bushblade

Nomad
Jul 5, 2003
367
2
47
West Yorkshire
www.bushblade.co.uk
I've just made this available for free download from my site too. There's been quite a few requests to make a printer friendly version with a white background, we do plan on doing this soon and will make it available for download when its completed.
 

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