[cdjk]

My mom got appendicitis on a cruise ship while it was about three days from port. They have lots of antibiotics, but surgery on board was never an option, although she was immediately transferred to an ER when they got into port.

In other cases passengers have been airlifted either to shore, or in one case a navy aircraft carrier, which is equipped to do surgery. That implies that reasonably advanced medical care is available ona ship, even if cruise ships are not setup to offer it. I'd link to the article, but I'm on a tablet and it's easy to find.