If something happens that is outside of the ship's ability to treat, they will either turn around to the nearest US port or, if that is not feasible, call for a medivac helicopter. That is what can really add up, as intens of thousands of dollars. So, we always buy insurance for at least medical and medical evacuation. Even with good primary insurance that does cover out of the country, nonewill cover medivac except travel insurance. It is actually very cheap. Around $50 for two of us for 7 days, as example.