Originally Posted by
Boston
You don't just need to be concerned with line strength, but the force you're putting on the object you're attaching to - which is the real concern with a taut line suspension.
So worst case a tree falls on you.
Let's look at a scenario, just to give you an idea. Assuming your 40ft span, let's sat the hammock itself sags 4ft from ridgeline to butt when loaded. you want to be 1 ft off the ground. So with an arrow straight suspension you'd need to attach 5 ft off the ground. This isn't practical of course, because the line will stretch when loaded - I don't have modulus of elasticity for amsteel handy so I'm going to make some assumptions.
Let's say it sags 1 ft. So you raise your suspension 1 foot higher - hanging at 6 ft high. You're hang angle will now be ~3.5 degree's. This mean's, with a 400 lb load, you're putting 3278lbs of force on the line, and 3272 lbs of force horizontally on the tree. Hope the roots are deep and strong!
OK, so lets raise it to 7 ft high, roughly the max you can easily reach from the ground. That's a 7.3* hang angle and still about 1540 lbs horizontally applied to the tree.
Not just worrying about tree's falling over, what kind of damage does this do to the tree? Are you using tree straps? Better ensure they're also rated for this high load. How are you connecting to the amsteel line? You'll have stress riser's reducing the breaking strength there too, most likely.
It sounds like this would be a permanent set up. Why not just use a ladder and hang the amsteel where it needs to be?
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