battleship eating a devil fruit sounds cool, but then it would have to contact the sea which cancels the power of Devil Fruit somewhat (this can be debate, but I don't want to. I do know that there are people that partial submerge in the water and use devil fruit all the time in the manga). But if that happens I don't think it would be a person eating a devil fruit, I'm thinking of a ship that eats a devil fruit would make more sense. This, not relating to the ability of the guys anyway.
Honestly, I'm stick and tired of fruit users. Straw-hat has powerful guys on their crew that doesn't have devil fruit ability. Zoro, Sanji, and Franky don't have devil fruit power. Where are these people on the enemy side. We need more people like Garp and Momonga who are just simply strong through training. I don't know what Sengokou has, I don't know if it's a devil fruit power, but I really hope it isn't.
When i see devil fruit fighting with devil fruit, especially in this war, it's a lot less strategy and more power against power. It's more fun when one side doesn't have the ability (Zoro vs Kaku) or neither side has the ability (Zoro vs the Zombie Samurai for example). Okay, so for every arc I just like Zoro's fight. But that's partly because he doesn't have any power.
Like with Rayleigh, Mihawk, or Sentoumaru fight and they don't have Devil Fruit, in a way it makes them more interesting (unless Mihawk ate some sort hawk zoan fruit or something that gave him enhance sight but it was never mentioned)
I hope Shiryuu doesn't have devil fruit power also. If he's just a guy who is really good at his sword, that will be enough for me. And in a way, that makes him scarier.