People often refer to their car and other people's as "she" ("she's a beauty") so you're is obviously wrong.

But no one who does that thinks they're using proper English!

"she" is absolutely proper English for a ship or boat, with a long history of use continuing into the present day, and many dictionaries also list a definition of "thing, especially machine" or something like that, though for non-ship/boat things the use of "she" is rather less common.