By Tom Richardson — BoatingLocal.com — Posted On February 23rd, 2011 - updated on March 9th, 2011
More details are emerging about the revolutionary 557-hp outboard introduced by Seven Marine at the Miami International Boat Show last week. BoatingLocal spoke with Seven Marine’s Brian Davis, who was busy fielding questions from a curious boating media abuzz over the groundbreaking engine.
Davis explained that the company’s mission was to create a large-horsepower outboard based on a reliable, proven automobile engine and which would bring outboard efficiency, speed and maneuverability to larger vessels. The new engine allows boatbuilders and designers to go with twin-outboard installations rather than triples, quads or inboards to save space, fuel, weight and drag. Davis confirmed that the engine is based on a 6.2-liter V8 General Motors LSA engine, and features a ZF transmission just below the engine block, 2 pinion gears and hydro-electric clutches. There is no shifting mechanism in the gearcase, which allows it to be surprisingly small for such a huge engine, resulting in less drag. The 1,000-pound engine (add another 100 pounds if ordered with the double-walled stainless exhaust) features an oversized exhaust and can be joystick-controlled in conjunction with a bow-thruster for precise dockside maneuvering. The engine will run on 87 to 92 octane gas, and comes with a limited 3-year warranty (10-year internal engine warranty).
Seven Marine, which based in Wisconsin, is currently working with independent boatbuilders and directly with customers to make the engine available to the public. The company worked closely with Intrepid Boats in Florida to rig a 37-foot cuddy with twin 557’s for the boat show debut. Sea trails will take place in March, so no word yet on fuel-burn and performance numbers. Initial projections and Seven Marine anaylsis projects that replacing triple 300 and 350 applications with twin 557′s should result in a 10% to 20% fuel efficiency gain at cruise. Pricing for the 557 is positioned below the price for similar inboard power, and premium to multiple outboard installations starting at $68,900. “For the boater who wants big inboard-type power and features with outboard performance, efficiency, and room in the boat, this is a value package,” says Davis. “For the outboard boater that wants to go farther faster, increasing range and operating performance, this is a new
level of deliverable.”