Mesh turn black&white triangles when rendering

Hi, I’m new to blender, and facing a strange problem now:

Try render the model and it appears strange(only the hull):

The hull has no material just as other part of the ship (and I’ve tried assign a default material to it but the problem remains):

confusing…any help?

You have overlapping faces.
Check you haven’t two objects by moving the ship, is there another ship visible.
Select all the vertices (A)
Remove double vertices (W / remove doubles)
Recalculate face normals (Ctrl+N)

‘overlapping faces’

After applied a mirror modifier I add another mirror…

Many thanks Richard