Knocking off a corner

I am trying to reproduce 19th century engineering here. I need to knock off the corner of the flat cyan “solid” so that it fairs into the gray “solid.” Obvious they will never match up because the gray extends beyond the cyan at the sides.

However, the desired effect would be to knock off the corner to the cyan roughly matches the gray where these is overlap.

The curvature only needs to extend an inch or two.

What might be a good approach to doing so?

It can publish parts of these files? it would be useful to provide the solution.

Do you have some photographic examples for reference of what you need?

Ok, cap USS Holland

Hmmm… If I’m understanding you correctly I’d copy the top edge of the back of the grey solid and split the curve and rejoin it so that you have the top curved part but not the long edges:

I’d then take a section further back where the deck is flatter and loft or Sweep2 to get the overall transition.

From that point I’d match the surfaces but you’d probably have to split it along the horizon and then use the pipe command to make a gap like so:

From there you can use a combination of BlendSrf and MatchSrf to get a continuous surface. But once you’ve created the basic geometery you can take sections and rebuild the curves into continuous elements and then Sweep/Loft a cleaner surface.

See if this can help.
bigjimslade.3dm (3.2 MB)

Thanks everyone for the suggestions. I will play around with these!