Which Vehicle Should I choice for ship

#1 You will have to implement the Watercraft resource into TGE. Do you want the player to be able to move around the ship, or are they just controlling the ship?

#2 How big of a difference would it make if he did want players to move around on the ships?

#3 Well, it would depend on which resources he implemented and how he would update DIF interiors plus detail DTS's as the ship moved, effective collision masking of his DTS models, how high-poly his DTS model was, whether the ship had multiple levels which would need to be zoned for performance, etc. It's not just "load and go".

#4 The watercraft resource is pretty limited... in fact if you look closely it's just a copy of the HoverVehicle class with very few changes. At the moment the best bet it picking up a game physics book and implementing your own new Vehicle derived class.