There are a lot of factors here when trying to figure out arrival time vs boarding time. Personally, I like to get on the ship as early as possible to have some lunch, get a drink and chill. Also, take care of any booking we may want to do, buy cruisenext certs, etc. I have noticed that there is a sweet spot on when you arrive and how long you may have to wait in the queue lines or the waiting area to board. So, either you check in early and wait in the waiting area or you wait in the extra-long queue lines and board a little later. If you arrive after 11 your chances of waiting in the queue lines goes up quite a bit. If you show up closer to 2pm the lines will be shorter, but you have lost about 2-3 hours of total on ship time. It is not exact science, just what I have observed.