In the 2000s, there was a cartoon series where the protagonist was an orange-haired female and they had a van that could transform into a rubber boat with the press of a button.
Yeah, that's what seems like the most plausible answer. I definitely remember there are some episodes that feature the bus becoming a boat, and the orange hair fits the teacher from the show. I could find some episodes that have the boat thing if OP thinks that could be it?
Atomic Betty maybe. Her Starcruiser could turn into a van and a submarine. The show is sort of obscure so I can understand why it might be not easy to recognize or remember.
There is a slight possibility, although I believe the orange-haired female looked somewhat different and very likely had freckles.
What I clearly remember is that there was an episode when their vehicle ran out of fuel and the fuel meter was shown with the pointer towards "E" (empty), and I think the intro song had a voice singing "na na na na na na na na na na na" (melody: 333-34-43-2-1-3-3).
Atomic Betty maybe. Her Starcruiser could turn into a van and a submarine. The show is sort of obscure so I can understand why it might be not easy to recognize or remember.
Rather unlikely. I think the protagonist looked different than her. Higher body-to-head ratio.
