What is a hospital ship?
A hospital ship is designed to be a floating hospital on the ocean or seas to offer medical treatment spanning from minor to major surgeries, prescribing medication, etc.
One may wonder when they were even invented and why. However, they are not a modern phenomenon, as they have existed since ancient times.
The navy of Athens had a ship called Therapia, and even the Roman Navy had a similar ship called Aesculapius. Their names and descriptions indicate they were hospital...
https://www.marineinsight.com/types-of-ships/largest-hospital-ships/