You're looking at a 5-passenger prototype SeaPhantom ground-effect boat, by David Borman. The prototype uses only a small outboard motor to reach 70 mph (a larger motor can get it up to 100+ mph).
Here's the SeaPhantom in action:
Hit play or go to Link [YouTube]
"Ground effect" [wiki] seems familiar, huh? - if you're wondering whether you've read it on Neatorama before, you'd be right. See Bigger is Better: 7 Insane Soviet Projects (#3 the Ekranoplan)