Nameaneh,
While you don't show a pic, it sounds like the PO closed of the entire rear of the boat from the companionway hatchway. Sounds strange though, and could make it real difficult to replace the keel winch guide bolt. I have an old V21 and that area is real important for storage in this "little" boat. Going in through the Lazarette is the only way normally to get to the inner edge of the transom since the styrofoam blocks(which should still be there for flotation) are usually in the way. My ladder has screws into a wood backing plate which I plan to replace with bolts and oversize fender washers after putting a coat of poly on the wood plank. I added a wood backing and did the same for the motor mount on the port side of mine.