A couple of years ago someone built a model submarine with an actual MagnetoHydroDynamic drive:

“Magnet Powered Submarine - The Hunt for Red October IRL!” https://www.youtube.com/watch?v=nFsiydplCtw

The corresponding blog entry includes the STL files for 3D-printing the submarine’s hull:

https://www.kjmagnetics.com/blog.asp?p=red-october