Well, I think I made a good start today.
It wasn't just dust, the boats must have been on display above an oven or something.
There was the same kind of gunky oily film that you get on the exhaust hood over your range, covering every inch of these boats.
Hours of elbow grease later, they are 90% better. They are now to the point that I can start working on them.
Here are some before and after pics.