Here is what I do. Find a very strong frame on something. I use the metal side rails on my trailer. Get 4 straps and put then through the donut and around the sides of the frame in a N,S,E,W fashion. Then tighten each strap to pull the donut into a larger circle. Slide the oar into the donut to the appropriate position and release the straps. Slide the straps out from donut and you are done.
Use the shortest straps possible, so there is not as much strap to pull out after the donut is on.
Karma is like this: If we set causes in motion the effects come back to us.