Don't trust Guetermann
because it is Guetermann. It is just another thread company making a range of threads, some appropriate, and others not --(including a full range of embroidery threads.) Still, with enough stitches of thread heavy enough not to be abraded and frayed or decomposed to the core by UV, strap-loops and channels can be sewn securely even with the wrong thread.
That said, if you bought Guetermann from a an outdoor specialist, it is likely the right thread in the Guetermann lineup.
On Amsteel breakage. Yes, it has been reported here, in structural ridge-lines (SRL), How? Well, start with 450lb bs material. then degrade it by tying knots in it instead of splicing, and the bs may be just 300lb. Now put a transient or "dynamic" load on it, and a cord explicitly designed to have no stretch and no energy absorbing capacity will snap.
Who to blame? Not the designer and fabricator, who expects the SRL to be no tighter than making it easy to make a horizontal Z in, between thumb and forefinger, which may be just 7% of the effective breaking strength.
Last edited by DemostiX; 12-31-2012 at 02:23..