TOPIC: Restoring a 1964 Dorsett San Juan

I'm about to splash the girl Ive been working on since last June. I've got a couple of questions and dont know the correct specific forums, so I'll start here.

There are two throughhulls, one each side. One had a plastic bag shoved into it, and the other ihas plastic rubber-banded over it. My best guess is one is for the sink and I have idea about the other. That's the side the marine toilet is on , but Ive already id'd that.

My other question is about getting a new thermostat. It's got a BB70 engine, and i cant find one anywhere. Is there an alternative or aftermarket version?

Thanks!