In message , The Natural Philosopher
writes
Boat hull resistance is purely a function of wetted area and speed.

Air resistance is more complex, because air is more compressible. Its
a function of frontal area and shape.


A displacement boat has a "natural" maximum speed (the hull speed)
dependent on the hull length. I've often wondered if something similar
applies to cars in air.

It might explain why in the old Omega, fuel consumption on the motorway
only went skywards over 70, but my current vehicle is bad over 60.
--
Bill