After a last sanding I tried to go back to paper model build.
I glued the first layer of the decks on the hull.
At the stem I found a mistake in my model. The deck part did not fit to the prepared hull. I don't know the reason for the mistake. Perhaps I worked not accurate enough.
But this doesn't matter, I have to fix it.
First I glued stripes of paper under the deck on the hull. Then I filled and sanded the bow different times until I was satisfied with the result.