Clip free end to boat.
Take bag to shore anchor. Length is not relevant as long as it reaches said anchor.
Take extra length of rope out of bag. Wrap extra rope abound tree, bush rock or sand stake.
Tie a couple half hitches with the free loop back to the main line. Maybe this is called "on a bite"?
I also keep a prussic loop on the line, down near the bag. This goes back to a Biner on the boat to snug it all up without dealing with the mess up at the anchor.
The whole rope never leaves the bag; mine is over 100' long.
(Seven two 0) 298-2242
(seven two 0)-298-2242