It has been three years since Massachusetts-based Imtra took over the Zipwake line of interceptors, and during that time, the team has been thinking big. In 2017, the Series S that Zipwake offered was for boats from 20 to 50 feet length overall. Now, Imtra has unveiled Series E, which expands the pitch-and-roll-controlling technology to yachts as large as 100 feet.
“The major restriction is the amount of lift generation you can get out of a unit,” says Jamie Simmons, Imtra’s product manager for Zipwake. “The Series S has a millimeter stroke on it. You have the blade going straight up and down in the water column to generate lift. When it was down, that blade was only 30 millimeters from top to bottom. You can only generate so much lift with a blade that size.”
The new Series E, by contrast, has a 60 mm stroke.
“The blade that comes down goes farther than on the Series S,” he says. “It gives you more lift generation, and the units are larger on the transom. The construction is more heavy-duty. It’s a larger blade, bigger moving parts—it just has to be more robust.”
The Series E components are part of the expanding line of Zipwake products that Imtra now offers. The company has been adding components that fit with different types of underwater hull shapes, such as chines and prop tunnels. Series E includes three straight, three tunnel and two chine interceptors. The three tunnel models (R500, R600 and R800) have different radii for prop tunnels of different sizes, while straight and intermediate blades can address different engine configurations, such as multiple outboards. Switching from a straight to a rounded blade between outboards, for instance, reduces the cavitational zone.
“With the straight edge, that zone was much larger,” Simmons says. “When you round the blade off, it brings that zone in.”
Going forward, he adds, Imtra’s goal is to have a wide range of Zipwake options. “We’re trying to have a solution for most every boat,” he says. “There will always be odd situations, but up to about 100 feet now with the Series E, more than likely, we can come up with a solution.”