Scout Boats in Summerville, S.C. is building a 67-foot, $5 million, quintuple-outboard boat called the 670 LX. This new flagship, expected to launch next year, will be the largest outboard-powered production boat ever built (longer than HCB’s Estrella 65) and, according to the builder, one of the fastest.
Co-designed with British superyacht studio Harrison Eidsgaard, the 670 LX will come in three models: fishing, sport and coupe. It will be Scout’s biggest offering by 14 feet. With five 600-hp Mercury V-12 Verados on the transom, it should run at least 52 knots. A draft of 2 feet, 7 inches means an owner can joystick this boat right up to a beach, raise the outboards and step off the fold-down stern platform to wade ashore.
Director of R&D Steve Potts Jr. — whose father, Steve Potts Sr., launched the company in the late ’80s — says the 670 would not have been possible several years ago. Scout has a 400,000-square-foot facility where 400 employees build more than two dozen models, from the 175 Sportfish center console to the 530 LXF. Ultimately, the decision to build the 670 LX revolved around engines like Mercury’s 600-hp Verados, since similar capabilities and dimensions wouldn’t be possible with inboards. The propeller shafts would have had to come in at too steep an angle to allow for a low, flat, fold-down stern, and the engine room would have been too cramped.
The steerable lower units also allow for the V-12 600s to be spaced closely together, permitting a reasonably narrow beam of 19 feet.
“It wasn’t that long ago that the biggest outboard was a 225,” Potts says. “The 600s are proven engines. The transom’s only so wide, so you can get them a lot tighter and closer together. You gotta be able to trailer it down the road, too.”
Scout relied on fluid dynamics modeling for the hull’s two-step, three-strake configuration. The vee-hull should have required at least the center engine to be stepped down and set lower than the others, but Scout wanted the deck of the engines to be flat at the stern. The modeling tested planing efficiency with a small, flat, upward notch laid into the hull to permit water to flow across the center propeller.
“We do a similar thing with the 53,” Potts says. “This one, we notched a bit more, simulated it, and it ran exactly the same simulated as it did with a vee-hull.”
Another challenge was making the hull strong enough to allow for fold-down gunwales to starboard and port. Scout worked with composites specialist Vectorply to design a stringer and hull shape. Potts compares the result to the hidden strengthening in convertible cars that can’t rely on roof reinforcement for frame strength. “The stringer’s pretty elaborate,” he says.
During the nearly yearlong design phase, Scout relied on CAD renderings to create the three-stateroom layout and hull design. The idea, Potts says, was to get to a point where the team could walk through the boat by strapping on virtual-reality goggles.
“We put the VR goggles on and walk down into the cabin,” says senior designer Jeff Summers. “The cabin kind of opens to a big sunroof on top of the console. So when you sit in the lounge, you can look all the way up to the sky, which is something that you wouldn’t notice unless you’re physically building the boat and sitting in it or putting the VR on.”
The 67-foot deck plug was built by the North Carolina composite design firm Symmetrix. This plug occupies a significant chunk of floor space in Scout’s R&D facility, alongside a five-axis router that sculpts a stern seat setup out of EPS foam. When it’s finished, the team can lift it into place and sit on it.
Summers says the plug had to be level, but Scout’s cement floor was imperfect, so Symmetrix brought in a machine that rolled a small steel ball across the floor and scanned for imperfections. “And this huge machine is taking pictures of it the whole time,” Summers says. “It’s taking thousands of measurements to see how far things are off. Once they bolted the plug in and leveled it, we’re within, like, thousandths of an inch.”
The boat’s upper cabin will be fiberglass and fully enclosable with air conditioning. It will be accessed via glass doors and opened to the world with automotive-style power windows. With the router and an ability to create rapid fiberglass layups for smaller pieces, Scout’s design crew can test whether configurations that looked good on CAD or in virtual reality are real-world serviceable. They also can check for details such as optimal placement for phone chargers, rod holders and cup holders.
During our visit to the factory, there also were life-size printouts of the stern deck and the components that will go beneath it: Seakeeper gyrostabilizer, pumps, tanks, hoses, wiring and genset.
“We’re designing it all on computer with VR in simulation and then basically mocking it up and walking through it and making sure it all works,” Potts says. “And that’s certainly been a challenge as far as the functionality. You can’t look at another boat and see what somebody else did in a certain situation. There’s not another boat like this. You just kind of figure it all out on your own.”
This article was originally published in the July 2023 issue.
