Or if your really brave, you could do this with a large course disk sander..
Takes some skill to control the big disk sanders.

The builders of my hull, Blue Water Boats did a nice neat job of it and I
believe it was done with a very large belt sanding machine. The chamfered
the 1" bulkheads back about a foot all around and that is how far their
hull/bulkhead attachment was carried on my 38 ft hull..


--
My opinion and experience. FWIW

Steve
s/v Good Intentions