As cool as a ship who ate a fruit would be… doesn’t that mean the ship can’t float? So unless it’s Laputa, idk if that works.
I believe pluton terraforms.
So, it would be producing a mineral layer between the ship itself and the water to avoid touching it.
In order to float, the ship needs to make an outer layer.
This is the biggest reason I never considered pluton eating a devil fruit, the fact that it would completely hamper its abilities to function as a ship.
But since I believe the ship can terraform and created the walls that serve as Wano's borders to begin with, it's possible it could create a layer of Vearth or minerals, to separate it from the water.
When underwater, it would be operated by its crew using its cyborg parts to move it when it can't move itself.
Is pluton can produce flame cloud like kaido, it should be able to float, too.