Quote Originally Posted by nanok View Post
on its own, tension in a line gets unintuitive enough when you go into details, when adding friction on a round object it can easily become very confusing to anyone.

your idea is right and i like it (we have the same intent i think): distribute the forces the best possible way. i would just suggest one thing to try with your method (the double wrap): add a marline spike hitch on the strap that goes to the hammock, and put the loop of the other end of the strap behind the toggle, instead of letting it slide freely on the webbing.
then center the connection inline with the suspension, and pull it tight, it should stay in place on the tree.
this way you ensure that both sides are sharing the load, and if the load is not spread 50/50, at least it's very close to that. this way you will achieve the same thing in terms of load distribution as my setup, but it's much easier to try out (as you just need to add a marline spike hitch and a toggle to try it out), and yes it means it will effectively make your webbing twice as wide (as far as the tree is concerned) and twice as strong, as long as the marline spike hitch is far enough from the tree (if the angle between the two sides of the strap going to the tree at the marline spike hitch is 120, you already might as well have done it the usual way, as each side takes full load. if it's more than 120 it's worse than usual way, if it's about 60 degrees, you get about .57 load on each side, from there improvements become marginal, at 30 degrees load is .51 on each side -- you get the picture, 0.5 is obviously the best possible; of course, the narrower the tree, the easier it is to achieve an accute angle, which is fortunate as it is typically the smaller younger trees that need the added protection most). as a rule of thumb, for getting 60degree you'd need the distance between the marline spike and the tree to be roughly half the diameter of the tree (if measuring the shortest distance), or about the diameter of the tree, if measuring from the tangent to the tree (so measuring on the webbing itself).
Good to keep in mind when using marginally rated rigging.

Recently I tested some light polyester webbing—3.3g/ft, which is coincidentally the same g/ft as the Kevlar I normally use—which has a rating of 900lbs vs the Kevlar at 2000lbs. My test venue (a favorite pair of trees in the local woods) features one small-ish and one large-ish tree.

Obviously (photo below) it's something of a long hang, and with the lightly-rated polyester webbing there was definitely some stretch involved here. So as I was bouncing gingerly on the hammock to get a feel for it, it occurred to me that I should consider the shallow angle formed by the webbing snugged close to that bigger tree and the resulting large force on the light webbing.