First, be aware that you will be required to check in at least one hour before the ship sails...so, you don't have until 5:00. Check your cruise documents for the exact window, as it might be more than one hour. It also means being checked in, not just arriving.
That said, are you on a non-stop flight? Do you have travel insurance that covers air delays? Both can work in your favor.
Should you become delayed, let the gate agent know you are on a cruise departing the same day, and perhaps they can get you on another flight. Also have a cell phone and the number of the airline. When our flight was cancelled before a cruise last year, I phoned the airline rather than stand in line with everyone else. They got us on a sister airline.
Yes, you're cutting it close. Being prepared is your best defense.