RE: Twin Screw Question
The wisdom that was passed to me was that turning one way was better for steering, turning the other was better for performance. Cant say tat I've really noted a difference either way. If modeling a real ship, copy that.
The Titanic, like most liners, was intended for running fast and straight - the rudder was more of a trim tab. Serious steering would have been done with differential engine speeds, and changing the speed of a huge great reciprocating engine going flat out was not an instant operation. Even today, 50-odd thousand tons doing 20Kt takes a lot of persuading to go in a new direction.