explored the world of MHD drive-powered superboats
. Short for "magnetohydrodynamic," MHD drives hoped to one day revolutionize ocean-going vessels by increasing their tops speeds to 100 knots, but the low efficiency of these experimental drives made them impractical for wide implementation.
A vast shape darts beneath the polar ice flows, and is gone, as silent as a living creature, but far swifter. Clad in steel, and traveling at over 100 miles per hour, it leaves only a mist-like trail of bubbles in its wake. There are no great screws or turbines churning the water. In fact, there is no sign of any sort of propulsion system at all. Instead, the huge underwater freighter is thrust through the depths by an invisible force generated by water rushing through tubes enclosed in sponsons at the submarine's sides.