check this site.
FreeShipPlans.com - Free Scale Model Ship Plans, Blueprints, Drawings, Tutorials and much more...
some plans more detailed than others. there is a category for tugs. i built the 'klimek'. you can also try to use a paper kit as a template. i am doing it for my current endless build of the gdansk tug 'taurus'. i also found a good vector drawing of the tug on the manufacturer's web site.
https://midcon.pl/wp-content/uploads...08/KK-B830.pdf
hope this helps