Those are both very interesting jeff
The big takeaway from the first video is that their sil poly tents ripped when it got very windy.
My silpoly tent ripped like that once. The fabric ripped about 3 inches above the tent stake tie out, perpendicular to the load. Like in that video. I assumed it was because I put a rock on it to keep the tent stake from pulling out, and I thought it tore because it was rubbing against the rock, but now I’m thinking it was just the weakness of poly.
He subjectively judged silpoly sagged only a little less than silnylon when wet. I compared nylon and poly grosgrain webbing. Pulled on them with a scale like in that video. The nylon stretched a lot more when dry. The poly stretched the same when wet, but the nylon stretched much more when wet. I measured with a ruler. I forget the numbers now, something like a 6 foot length of poly stretched 1 inch with a 20 pound load. The nylon stretched 3 inches dry, an additional 2 inches when wet. That’s grosgrain not fabric.
He said the sagging was because the nylon absorbs water which makes it heavier which causes it to sag.
I don’t think that’s what’s happening – the fibers of nylon actually stretch more when they get wet. Based on my stretching of nylon and poly grosgrain.
When the mids collected snow, you can see how the length and width inside decreased. That’s what I’ve experienced – ill wake up after it’s snowed and all the walls are moving in on me. This us a weakness of mids, because the walls are angled. On the other hand, you can just tap the walls from the inside and the snow will slide off, restoring the internal length and width.
And when snow accumulates on the outside of the fabric, there is a huge amount of condensation inside, because the snow is cold.
.
