Hello... Is this close to what you are asking for then... Nearing 2300 lbs. DISP... SH.
MINI TUG
design Lev Zaburdaev 3D Oceanair
This is an example of one of the mini tugboats that you can build with the plans from Berkeleyengineering@yahoo.com
An old tug layed up on 4th of July Creek in Seward Alaska. She was used for hauling rafts of timber around.