I have gone through the same trials,... trying to contact shipyards for information to build models.
99.9% of them will not respond, the 0.01 percent that do will cite Copyright issues.
When I do find that Nth percent response that will assist me with information, I am then bound by
a Non Disclosure Agreement, and can not share the plans.
Karstensens is one of those shipyards that don't respond. It is an engineering /client copyright issue that
prevents them from sharing the data we would like to build models.
I was told by an associate, that he could get me trawler info from a UK shipyard, but I was jazzing on the
Karstensens designs, and "lines". It was a German hobbyist that produced the lines for the ST-140.
And I would be happy to share a copy if that is what you would like to build.