Planking on a carvel hull is tappered and curved.. Sometimes, in the area of
the turn of the bilge the plank will be planed with a hollow to accomodate
the radius. Vessels with a lot of shape in the stern or with 'tumble home'
each plank will be either tappered down to a couple inches or will be
hollowed out to fit the radius of the transom..

It's been 40+ years since I did any carvel planking but I think I remember
the term for planing a inside radius was 'backing out' and the special plane
was a 'backing out plane'..

If you were able to take one of the planks and lay it out flat (not likely)
it would not be anything close to straight.. the plank is cut to shape to
utimately form uniform seams and the plank isn't suppose to be Edge Set (I
have edge set planks but never more than a 1/4 the thickness of the plank).


--
My opinion and experience. FWIW

Steve
s/v Good Intentions