If you had to pick two high-performance cars that have the least in common, a Porsche and a Viper would surely have to be in the mix. In terms of roadgoing vehicles, these two share little. So they turned to the water, and Fearless is the company that led them there.

The Miami-based custom yachtbuilder has brought both onboard (so to speak) for a range of speedboats, penned by Porsche Design and powered by marinized Dodge Viper engines. The lineup starts with this 28-foot, 525-horsepower speedboat with seating for five that's's capable of reaching 70 knots (~80 mph) on what its German designers termed "the aquabahn." Yours for only $300,000.

Looking worlds better than the Porsche-designed land-yacht we reported on previously, the 28' runabout is only the first in a range of models that will be capped by a 150' flagship launching (literally) in 2010. A 44-footer is due next year, followed by a 68 before the penultimate 125 is set to appear in 2009.

This isn't the first crossover between automotive design and shipyards – Ferrari's venture into the water with Riva, and the more recent Andare Attivo come to mind. But having grown up around powerboats, this writer can tell you the Porsche-designed Fearless motoryachts appear to be among the most shapely.

[Source: Fearless Yachts via Kicking Tires]