Hi, I have been lightweight "bushcraft" camping several times out in the wild, using a hammock under a tarp, with both strung between the same two trees. The tarp is hung under a taut ridge line via its three built in securing loops. The tarp is tensioned along this ridge line using comms cord Prussic knots on each end.
The knot in the first end of this ridge line is the most important knot, as it has to be easy to tie, easy to adjust, very secure under load, able to be easily tied with one hand (in case you have accidentaly lost the use of one hand), suitable for left or right handed people, able to be tied above you, and always, quick release.
I tried using several commonly available knots for this purpose but none of them could meet all the latter criteria at the same time.
Ray Mears recommends the Evenk Knot (Also known as the Siberian Hitch) but I find it rediculously complicated to tie. It also requires two hands to tie it, it is directional so it could be difficult for either left or right handed people to tie and it cannot be tied above your head easily, if at all.
So I invented my own knot for the job which I called "The First End Tarp Knot". Although quick release I became unhappy with it and wanted a knot that was even quicker to release, so I came up with a simple interlocking double slip hitch, I call simply "The Tarp Knot".
It is the only knot I know that meets
all of the the above criteria.
Whether it is a brand new knot or just an old knot re-discovered remains to be seen but I will try to post some pics later showing how to tie it so you can try it yourself and make your own mind up. Meanwhile I have posted a youtube video showing how to tie my new(?) Tarp Knot:
http://www.youtube.com/watch?v=y3jmpXL4Kcw&feature=youtu.be