One of the most striking sights at recent boat shows was HCB's 65 Estrella—the world's largest center-console—and her five Seven Marine 627sv outboards. These engines deliver 3,135 horsepower and, according to HCB, drive the boat at a 39-knot cruising speed and a 56-knot top speed.
While the 65 Estrella has plenty of innovative features, it’s those 627sv engines—the most powerful outboards available—that are driving the project’s success and sparking possibilities for other boatbuilders.
“The primary technology that sets Seven Marine’s outboards apart is that our powerhead is mounted horizontally, like a car, versus vertically, like a traditional outboard,” says Brian Davis, Seven Marine’s co-founder and vice president.
Davis says the hurdles in developing the 627sv were substantial: “We had to deliver big horsepower in an arrangement that can push big boats,” he says. Seven Marine employed GM’s 6.2-liter supercharged V-8 powerhead, moved the gear shifting from the engine’s lower unit to a dedicated transmission in its middle section, and developed a lower unit that efficiently transfers power to the water. “We utilized twin-pinion technology and sterndrive-type contra-rotating duoprop technology,” Davis says, adding that this resulted in smaller-diameter, lower-drag shafts and torpedoes.