I dunno if we suddenly weigh more. The others are able to pull us up out of the water if we fall in. Usually, it's Luffy.

[Because, of course it is. Still, Chopper can't deny that it would be nice. To be able to cool off. He's not necessarily considering the idea of something like what people might use to carry babies. But something like a baby sling to carry him would probably work, given his usually smaller size probably being about right.]

You think it would work? I guess. Maybe we can try?