"I have never been on a boat, but I have been on an airplane."

Translation: Eu nunca estive em um barco, mas eu estive em um avião.

[Luso-canadian]

I'm quite sure it is acceptable to say "Nunca andei de barco..." rather than "... em um barco... the former means I have never been on one/a boat or any boat ever, whereas the latter, the acceptable answer, emphasizes 'one/a'. Anyone disagree?

[Paulenrique]

for me both work equally, but surely "andei" is the most common way one would say that! (by the way, we hardly ever use "em um" but "num"

[jackit]

Thanks Paulenrique, exactly the clarification I was looking for. I put "num" and was surprised to find "em um" was also accepted as correct.

[niamhie3]

Is barco used for both ships and boats? Are there any other words used to distinguish between them?

[Paulenrique]

For ships we frequently use navios.

[AndyChav]

What about "Eu nunca era em um barco, mas eu era em um avião"?