A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Date: 2016 Feb 6, 15:39 -0800
you asked "Wouldn't it still be 30 Martian nautical miles?"
I had exactly the same thought! The very idea of a NM is that it is a minute of arc and I see no other purpose for it. For the distance to the nearest gas station, when I am low on gas, I use kilometers; but that's just me.
If it's true what I read on Wikipedia, that there is even a definition of a Marsian second. So it would all fit nicely together.