Make a Ship with Sketchup should be a big Challenge :)
Best export from Sketchup is OBJ Format
And after find free prog like Amapi 6.1
http://forums.polyloop.net/software-misc-logiciels-divers/
(You must just post one message for download it)
Reload your OBJ format in Amapi and export it as Iges Format for moi

Ps Seems the Iges don't work from Amapi 6.1 :(
In fact seems you must only draw in nurbs mode (and not in poly) when you want export in Moi in Iges Format from Amapi 6.1 !

Best ist use this plug
before Image in background will be permit in moi :)
http://home.insightbb.com/~ryanvm/tinyutilities/vitrite/