You guys showed me how to do it, so I shared it with the readers of the SNO blog:
Adjustable Guy Lines Without Hardware article
Prussik's are great and can be used for many things
Nice! Great vid. I can see and understand what you are doing easily. Thanks for making / sharing this.
Great Vid... Explained well
Great video. I do the reverse of your set up. I have the continuous loop prusik larksheaded on the tarp and the fixed loop goes to the stake. This allows adjustment from under the tarp which is handy in wet weather. Also it allows the guyline to be adjusted very short (as short as 4 inches on my guylines) if I want the tarp to be very close to the ground.
Don't let life get in the way of living.
Here is my version which is the same as gmctr with the addition of a shock cord loop.
I also tie off the end of the guy line to the tie-out on the tarp as a fail safe in case the shock cord breaks.
The other end of the guy line is attached to the stake with a marlin spike hitch.
"Life is a Project!"