The correct answer is the word 'christen' Also, we sail on ships, not in them.

The verb to 'entitle' refers to a title - for example of a book - and is usually in the passive form. For example 'I read a book entitled 'xxx'. ' When you give something a name, the transitive verb is 'to name'. The ceremonial words 'I name this ship xx. God bless her and all who sail in her' is an absolutely standard formula. All ships which have a launching ceremony are launched with these words, at least in Britain. Needless to say, italki is a fascinating source of information. Until I saw Jerry's answer above, I wasn't aware that Americans said 'christen' rather than name, and 'on' rather than 'in' in the same situation.

Porque "Titanic" es un nombre, no es un título. Se dice: "se llamo este barco "Titanic" y no "se titulo este barco "Titanic".

That might be the case in the US, but not in the UK Jerry, and the Titanic was a UK ship...which is probably why is wasn't unsinkable :-). According to a quick internet search "There was no christening ceremony for Titanic in Belfast. ... chairman J Bruce Ismay, was reported to have said quietly, 'I name this ship the Titanic, and may God ..." https://books.google.co.uk/books?id=q2GtQq4zmiQC&pg=PA20&lpg=PA20&dq=In+name+this+ship+Titanic&source=bl&ots=Wbg3j7jk1l&sig=02xEpyewni2i6FiTXFi5uDmYAwM&hl=en&sa=X&ved=0ahUKEwj53obW-bLRAhWFMyYKHWQUDj0Q6AEIUTAJ#v=onepage&q=In%20name%20this%20ship%20Titanic&f=false We also use 'in' for sailing in ships, and we don't normally say 'christen'. The normal phrase is "I name this ship..., may God bless her and all who sail in her." We can use 'name' as a verb Carlos meaning 'to give a name to something/someone'. You can't use 'entitle' in the same way as it doesn't have quite the same meaning.

¨Entitle¨ has at least two definitions. Although one definition is similar to the definition for ¨name¨, that is the less common usage, so ¨entitle a ship¨ sounds very unnatural. Jerry is correct that there is a tradition of ¨christening¨ a ship, a formal ceremony when the ship is given a name, but the way you phrased the question sounded like it was from a test that you had taken. So of the two choices you asked about, ¨name¨ is definitely better. Here is what come up for the definition of ¨entitle¨ in Google. en·ti·tle inˈtīdl,enˈtīdl/ verb 1. give (someone) a legal right or a just claim to receive or do something. "employees are normally entitled to severance pay" synonyms: qualify, make eligible, authorize, allow, permit; More 2. give (something, especially a text or work of art) a particular title. "an article entitled “The Harried Society.”"