I run a full length ridgeline beneath my tarp, with the idea it will take some strain off the tarp ridge, and since it is beneath the tarp, would help with any structural load (think snow). I leave it permanently attached and the tarp ridgeline is secured to the ridgeline with prussics for the ability to slide the tarp anywhere along the line, and for tightening the tarp. One end of the ridgeline is attached to the tree with a toggle, the other at the moment I'm using a figure nine. I would prefer to use a true trucker's hitch (the loop is made with a simple hitch, not a knot) but the yellow Lash It/Zing It will not hold, so I'm still exploring options there. I finally get to my question: does the line under the tarp add needed strength and support, or is it merely a figment of my imagination which is not really needed??