What to pack for the trip

I was getting stressed because I didn't know what to pack for my trip.  I mean, it’s not as if I’m going on a cruise ship where people get dressed to the nines every evening, yet I’m also not going to be down and dirty with the containers (at least, I HOPE not!)  So I need to strike a balance: smartish wear for meals in the Officer’s Mess, yet comfortable and sensible seaworthy clothes & shoes, especially for walking around in ports of call and on deck.