Hi harrin.
A friend of mine has one. He is using a servo motor for power, modified to give it a better neutral position.
The only real problem he found, and this may be just his building method, was that when all the metal fittings were fitted on the model, the centre of vertical gravity was to high. So the model was in danger of turning turtle.
He removed the top most fittings, and it made much better.
I have a Lindberg American Diesel Tug at 350mm with the hull sides raised 7mm (would only notice to a purest builder) with a cassette motor, powered by four AA batteries which works well, with long run times.
But if you want e cheap model the is really good, though not an exact scale model of anything in particular, then I would recommend Thomas the 12 inch Tug. This was a free plan in model boats mag a couple of years ago. Works well as it has plenty of reserve buoyancy, and a broad beam. Best of all, it's almost free to build.
Bob