Looks like fun. Is that a modified Revell Harbour Tug model in between the two larger tugs? If I ever get back to modeling I hope to try and use the hull from one of those as a freelanced HO scale fish tug. It would be about 63 scale feet long, so on the big side for a Great Lakes fish tug, but some prototypes are that long. I motorized a Revell Harbour tug kit ions ago as a teenager, but that was long before I even knew what remote control was. You just turned it on and set the rudder and let it go in circles.
Anyway, it would be tight fit but I think 2 micro servos (one converted for propulsion), a receiver and a battery would fit and float in that tiny hull, but it might take a bit of planning.
RC Tug
RC Tug
Here is a tug I am working on as inspired by the other modelers. The one in the back is a stock Lindberg Kit converted to RC. And now trying my hand at modifying another kit to be a “railroad tug”. Thank you Tom Hynes, N. Schultheiss, Richard Jenkins and Matt Duncan for all the info they have posted for others to read and study! Thanks boatnerd people!