How is English important for my job or future

I am a college student and I entered the college in order to be a mate.Becoming a mate is my dream.
In the future, if I become a mate, I will have to use only English in the ship.This is because the members of crew communicate in English.
So, I study English very hard even if I am poor at English. For my dream , I must master English .Now I have four English classes in a week, but this is not enough to get  able to use English fluently, so I need to study English by myself.
For me ,English is a convenient tool to communicate with foreign people and a key of my dream.