HI
Have you looked at 3D printing your paddle wheels,I had my 1:200 scale model Great Eastern paddles made this way, they look great mind you as they have 15 paddle blades per wheel they are not very efficient.as there too many paddles in the water at one time. One paddle just coming out,one in,and one ready to enter the water for better
Or make them from plastic sheet { I think its ABS that I used } to make the paddle for my 1:36 Eccleshall tug.
. Have a look at the Paddle Ducks Forum they can help you.
Cheers
Hutch