You could look at it the other way too Mark, tying the ridgeline separately allows you to leave the tarp in a dry bag, once the line is up you clip one end on and move to the other end. You can even clip the dry bag onto the ridgeline to keep it up off the floor and then slide it down.Great tutorial Chris,
As an adendum. I tend to leave my ridgeline attached to my tarp. When packing I fold the whole thing and roll toward the ridge and then leave one end of my ridgeline (always the same one) hanging out of the bag. I then wrap this around the bag and tuck the end under.
This means that when i set up again, my 1st securing knot is done before I take the tarp out of the bag. This stops it dragging on the ground, through thorns etc. and makes it easier to handle in high winds and stuff.
Hope this helps
that looks very much like an alpine butterfly and they are great for creating a fixed loop in a ropeThe pictures strike me as being particularly clear. You must have put a lot of thought into that, Chris.
In 1986 my wife gave me a copy of The Ashley Book of Knots. I browse through it occasionally looking for interesting items. One that caught my eye a few weeks ago is The Span Loop (number 1049 in that book). Clifford Ashley writes "This is exceptionally easy to untie and is, moreover, one of the strongest and most secure of the series."
The knot can be tied in a span without access to the ends.
I tried this whilst camping out last Thursday night. It was used in the ridge line of my tarp in order to provide tension. The next day I came to undo it and found that indeed it was remarkably easy to untie.
I shall try and attach an illustration.