O: First of all, let's discuss the problem of Devil Fruit users bathing themselves. People who have eaten a Devil Fruit are "hated" by the sea, and cannot swim. The "sea" here can refer to anything from rivers, pools and baths to any kind of standing water. On a worldwide level, they are all the "sea." When these people enter the water, not only can they not use their powers, they have trouble moving their bodies at all. They might be able to struggle a bit, but it wouldn't do much good. That's if their entire bodies are submerged in the "sea." With less than half the body or just the limbs, it gets easier.
