I am not suggesting that "hospital ship" requires a certain size or dedication to medical capabilities. My point is rather that the term itself is just a catch all for a wide variety of medical support capability and as such not a lot better than eg "cargo ship".Even then, I think the tweet is a bit odd as it seems to suggest that hospital ships (or rather medical ships) need to be a certain size to qualify as such, and that if they're smaller then they would somehow be more.... Multirole and less focused on the primary medical mission?
...
For the same reason I regularly qualify as to what the US ships are really designed to do vs eg Peace Ark. But Twitter type limits and all.
PS: "Medical support ship" I guess in that regard is a far better term.