Question: Could всё на х*й or всё на фиг be used with the same meaning as всё зря?

(It seems to me that if one is going to get a tattoo like a sailor, one should cuss like a sailor!)

P.S. As long as I'm on the subject, what is the exact difference between моряк and матрос? Can they both be used when talking about "the Navy" in military contexts?