We noticed a couple of years ago that Royal Caribbean took its hand sanitizers off its ships. I think there is still one to use when you board the ship in some ports.
We carry sanitizer with us on land and sea, just to give it our best shot. It was proven, though, that hand sanitizers don't prevent certain kinds of viruses like norovirus. Only hand washing with soap and water can do that. But it's the next best thing, and probably does prevent a bunch of other potential risks.