Translation:Let's go captain, we take a shower.
The translation is correct. Please note that in Italian is: Let's MAKE a shower (FACCIAMO) rather than let's TAKE a shower (PRENDIAMO). Prendiamo una doccia is wrong. Just in case you try to directly translate from English ; )
It could even be an invitation to the captain: let's go captain, let's take a shower. Problably said to Schettino just prior to running aground his boat.
What I pictured in my mind was a mom teasing her son that just came back from playing pirates or something, but I like your version more :)
In Australian and British English one definitely has a shower! We are also very aware that Americans "take" showers, which is not often used in BE countries.
f.formica's interpretation makes perfect sense actually, but I still can't stop laughing!
But translated as 'we have a shower' is wrong, because that does not mean 'we take a shower'. You would only say 'we have a shower' in reply to a question such as 'In your house do you have a bath or a shower?'
This is wrong; in British English, we have a shower (or a bath) rather than 'taking' a shower.
No: it's a bit more complicated. In English certainly we would say 'I am going to have a shower,' or 'Are you going to have a shower?', or 'I have had a shower,' all meaning that the subjects have showered or are going to have a shower. But that usage does not apply when the pronoun 'we' is used. Again you would say 'We have had showers,' or 'We are going to have showers', but the expression 'We have a shower,' can only be possessive.
but saying "we are having a shower" would indicate showering. Also "when we wake up we have a shower" would indicate showering, not possessing a shower.
English is not my mother tongue, but I'll still guess. Would it make sense to say such a sentence on the event of christening a ship with champagne, with the word "shower" referring to a celebration, something similar to a "baby shower"?
I don't think so, because we don't refer to christenings as "showers." Only certain celebrations count as "showers" - baby showers, as you say, and bridal showers. Why, I have no idea...(maybe because the parents or bride to be are "showered" with presents, whereas you don't shower a boat with presents when you christen it?)