Back on PC.
The trippy bit down 'ere, is to balance the anchor,chain and correct length of line on the prow (easy on a rib), shove the boat stern first away from the shore paying out the trip line as she goes. When the boat is at the required distance from the shore, give the trip line a tug and it pulls the anchor into the water. Attach the shore end of the trip line to a rock or small folding anchor. Pull on trip line to recover boat.
Be sure to attach the trip line to the blade end of the anchor, there's usually a hole, otherwise you wont pull it out.
Also, if the trip line is a bit floaty, you don't need clowns motoring about between the anchored boat and the shore.
I tend to use it in the eve after the clueless wonders have packed up and ferked off. Saves me going for a swim after a Glass of Rioja and a sossage.