The skin hull personally doesn't work the first time either. And I am the designer! It is a part very difficult job...
There are many factors. mainly the thickness of the paper.
With sandpaper you have to smooth the card skeleton, especially at the stern of the boat. the skin has to sit well. Never never force.
I always include more distance in the stern and bow skin to cut the excess.
Good work popeye!
I follow your constructions on your youtube channel!
I forgot ... the boat did not have a Bilge Keel.
SHIPMODELL: SS CIMBRIA ocean liner 1867