Originally Posted by
NativePaul
56104 motors are totally inappropriate for this build, they are FAR too big, if you use these you will use more power just to spin the motors themselves than you would otherwise use to push the boat at its scale speed.
You may think you want the weight to ballast the ship down to its waterline, but you would be much better off using batteries or even lead as your ballast. much longer runtimes with lead ballast due to the motor running much more efficiently at the power level you are after, and hugely longer if you use bigger batteries for ballast instead.
What sort of running do you expect to do, brushless motors are much more efficient at high throttle loads, but brushed motors are more efficient at low throttle loads, so if you intend on spending most of your time with just a sniff of throttle on and plenty of power in reserve (as is often the case with tug boats) you might want to consider a brushed alternative.
I can see why you don't want to use the motors Peter Sripol used in his, $130 each is a lot of money for tug motors. I think he only used them as he got them for free, even they at under 1/5th of the mass of the sss 56104 they looked like being way too much for the hull at full throttle. I would consider something even smaller like the 3510 he mentioned designing it for, if you can find one with as low KV. YGE and their Chinese YEP clones have a very smooth throttle, which will be more important to you than it is for many FE runners.