The hatch was a cheap piece of plastic. I used it as a mold to build a new fiberglass hatch. But you don't have one to use as a mold. So, use cardboard and duct tape to create a hatch, then cover the mold with Saran and glass over it.
Tell me about the rudder. Is it missing? I have one in my basement. I still have the original tiller because it saved my life a time or two. I put it on every boat I have owned.