Is there a name for that boat? How can I find out how to build one?

Roger In Sweden they were/are simply called river boats.

They are called river boats here in Finland too. I did find a PDF-file
with instructions and drawings - unfortunately the text is in Finnish,
but maybe a boat builder like you can make some sense of the obscure
drawings:

http://www.hirvas-vaappu.com/VENE%20OHJEET.pdf

--
Jarmo Hurri

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