How do you place structures/boats made in the editor into an exploration or creative map?

[zarwil 393]

For example; if I have built a ship in the editor in a completely empty world, is it possible to then copy the ship into another world? I want to try the ship in water. If I generate terrain in the editor it overwrites the ship and you can't reverse the action (frustrating to find out, luckily I had a backup from a earlier so I only lost an hour of progress...).