The horn echo is recorded sound but it sounds like it is echoing off of the nearby buildings but it really is not.
It has two electric motors driving two Graupner Schottle drives. The drives swivel 180 degrees so the boat is very manuverable both forward and reverse.
Easier to build I think because of all the flat surfaces and 90 degree corners. Also not to scale so I could do anything I was capable of creating.