Shipping out and Graduate school

I apologize if this is in the wrong section. This is my first time posting.

As of right now I am in my last year of school at suny maritime

I have started looking into going to graduate school after i finish this year.

assuming all goes well i will graduate with a 3rd mates license

when speaking to the people at grad school admissions i am allowed to work it where i could do one semester until i finish if i like

i was hoping to find a way that i could work as a 3rd mate and do this one semester a year plan at the same time

some people have told me is that union jobs can sometimes make this possible depending on the situation?

i was wondering if anyone had any experience with something like this or any advice about this in general?

thank you