Tested my cuben fiber tarp last night. They were calling for rain so I set it up in the yard. We had a storm that had 50 mph winds. I did not get wet but the tarp seemed like it was going to blow away. Tuned out the Prussic Knots slipped on both ends. I changed back to the Whoopee set up I had. Its a little heaver 1/2 oz but I know I won't slip. Is thes just a falt of the PRUSSIC knot?