I know everyone loves to talk about how great their hammock is and post pics of their feet, but if you want to know anything about the strength of a design you need failure data. Hence this post of negative results.
I made this hammock last spring. It's Dupont Tyvek housewrap, 9 feet long (didn't measure hammock width), with double sheet bends at either end. The blue cord is a structural ridgeline (Amsteel) and it was hung with a reasonable sag angle (see photos). It was in backyard use (i.e rarely longer than a nap per day) for a few months last winter and this spring I'd used it about four times prior to failure. It was stored folded in a bag.
Today I hung it and got in. There was no obvious damage when I hung it. After about 15 seconds of lying down (i.e. all initial transient loading had died out), it failed with a bang. No identifiable sound of ripping. 90% of the width tore within milliseconds. When I pulled on the tear after failure, it continued to tear with *very* little force (less than tearing paper). I weigh about 175 lb.