Q:

ship - which or who

As I know, we use she for ship instead of it.
How we make description for ship?
"The ship which left the harbour at..." 
or
"The ship who left the harbour at..." 
I have been told it is with which, but I found these novels:

The Ship Who Sang
The Ship Who Searched

Also I made two simple searches in Google for exact matches. There results are:

"ship who" - 384 000 matches
"ship which" - 495 000 matches

So which is the correct? Are both cases possible?

A:

Using "she" to describe ships is a poetic tradition.  It doesn't make them into women.  They're still objects.  Use "which" or "that". 
The two novels you mention are artistic creations - I could write a book called "The rock who sang" and that wouldn't change the meaning of "rock" as far as the English language was concerned.
As for your google search, most of the top results for "ship who" (with quotes) refer to the novel you mentioned already, so we can discount them as evidence for anything relevant to the actual language itself.  If I do a search for
"ship who" - "the ship who sang"

ie, removing results with "the ship who sang" in them it goes down to 34,000.
Incidentally, searching for "ship that" gave 6.5 million results.
At the best of times, comparing the number of google search results is a very unreliable way of establishing the correctness of anything.  More useful is google ngrams, which looks at the content of books, which are a more reliable way to view the idiomatic use of words.  Eg

