I keep trying to picture what kind of boat everybody is thinking of and I assume there are many different ideas. Some posters have suggested that the boat might have been too small to transport two bodies. That would be a very small boat and swinging bats or crow bars with enough force to kill might tip the thing over. I would have imagined a bigger boat. A pontoon would be the easiest for both bringing body (or live person) on board and certainly easier for pushing the body overboard. Certainly wouldn't tip over with head bashing going on. A bass boat or deck boat would be fast and I wouldn't want to be at troll speed transport a corpse. Bass boat not so good for committing the murder, deck boar better, but I don't see that either,
I have changed my mind about the boat. I think the perp's came by a road vehicle and took Shirley that way after she had been killed. Later she would be put on the boat either at the perp's house or driven to where the perp had access to a boat. If the boat were on a trailer, I presume it would be put in at the Long Shoals boat ramp which is very near the recovery site.
I can't picture somebody taking the risk of parading Shirley live or dead down to her dock.
Motive for taking Shirley? Already been discussed here. Confuse LE and leave open the possibility that she had done this herself, which is nuts.
They did NOT mean for her body to be found. Sills has said that in several different ways,
JMO, can't wait to hear yours.