If you line the inside of the keel with strips of lead it makes the model a lot more stable, to do this you have to test the correct ballest in the bath. A single 6v motor can be used to drive the centre prop (I know this is not as the real item but needs must) with a low weight reciever and esc you can make quite a good radio controlled boat out of this model.
This is the version of the titanic that I applied the plastic magic treatment to and provided you dont go to fast the model is quite stable in calm water.
Sam