An Eco-Friendly Hybrid Boat is the First Of Its Kind

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Belafonte is a 35-foot, 20-passenger power cat and the first Coast Guard-inspected vessel with electric power certified to carry more than six passengers for near-coastal use.

Belafonte is a 35-foot, 20-passenger power cat and the first Coast Guard-inspected vessel with electric power certified to carry more than six passengers for near-coastal use.

As with so many things in boating, the story of Belafonte begins with another boat: Reef Express.

Reef Express, a 57-foot power catamaran, takes a few dozen people at a time on snorkeling trips out of Key West, Florida. A man who knew the boat found out about its St. Croix-based designer, Dave Walworth, and had a connection to one of the boat’s build-team members, Joe Kitchell.

The man had small boats that take tourists on day trips, and he had an idea for a new one. He wanted Walworth to draw it and Kitchell to build it, for a specific itinerary. “What this boat is intended to do is go out for three hours or so,” Walworth says. “In Key West, there are these inshore dolphins that live in the area, and people want to watch them. Then he wants to go over to a mooring or an anchoring spot where people can go snorkeling, and then back to the dock. He’s planning two trips a day.”

The man wants to sell the day trips as eco-tours, which got him thinking about hybrid propulsion — an unusual choice for these types of commercial applications. “Electric power has the oomph, but it doesn’t have the range,” Walworth says. “It’s OK because this owner doesn’t need a lot of range.”

Thus began the design and construction of Belafonte, a 35-foot, 20-passenger power cat that is expected to launch this summer at Kitchell Composites in California. Belafonte is being built with epoxy resin infusion — Kitchell’s specialty — and is believed to be the first Coast Guard-inspected vessel with electric power certified to carry more than six passengers for near-coastal use.

Torqeedo Deep Blue 40 engines will be in each hull, fed by BMW i3 lithium-ion batteries for a cruising speed of 14 knots. A diesel generator will also be aboard. “Torqeedo doesn’t have a lot of these packages out there, and there’s no system like this that’s been approved by the Coast Guard,” Kitchell says. “That’s been our big challenge. We might have to swap out a breaker, things like that, to get approval from the Coast Guard. There’s a lot of power in this thing, and they’ve never dealt with it before.”

One change to the original design, Walworth and Kitchell say, was the need to build a stainless-steel box around the batteries. “It’s been a steep learning curve,” Walworth says. “The regulations don’t exist. In the Coast Guard world, the small-passenger-boat world, it’s a pretty new way to power a boat. There’s such a thing as a diesel-electric drive, which lots of cruise ships have, but they don’t have the giant lithium-ion batteries. A few years ago, there was an issue with them catching fire on planes. I think the battery makers have a pretty good handle on that now, but we had to do some special things, like build a box around the battery, do some things with the control system.

Epoxy resin infusion is Kitchell’s specialty— it keeps the weight and the expenses of the build lower.

Epoxy resin infusion is Kitchell’s specialty— it keeps the weight and the expenses of the build lower.

“If it was a diesel boat, there’s already a written set of regulations,” he adds. “They’re in the book, and you check them off. This boat has to meet everything the diesel boats do but also have the lithium-ion battery in there.”

The benefits of electric propulsion, Walworth says, are worth the effort. When Belafonte hits the water, she’s expected to burn as little as 3 gallons of fuel on each 3½-hour tour. “Even if it’s 6 gallons a trip, that’s amazing,” Walworth says. “It’s 12 gallons a day for two trips.”

The idea is that Belafonte will cruise to the inshore dolphins using the diesel generator and batteries, then slow to a near idle once the dolphins are found. “Because it’s an electric motor, the boat isn’t going to stall,” Walworth says. “He can go as slow as he wants with the dolphins.”

When he runs from the dolphins to the mooring, Walworth says, the crew can talk to the guests about water safety before they go snorkeling. “The boat will be nice and quiet,” he says. “And then on the mooring while the people are snorkeling, he can charge the batteries with the generator. So by the time he gets back to the dock, he’ll have a pretty much used-up battery at the end of the day, depleted to about 20 percent. He can charge it overnight and be ready to go again in the morning.”

Walworth’s Reef Express design first caught the owner’s eye.

Walworth’s Reef Express design first caught the owner’s eye.

Each of the two batteries and the generator can drive the boat on its own, for redundancy in case of an emergency. And there will be about 2 kilowatts worth of power coming from solar panels on Belafonte’s top to help with recharging. “In an ideal world, he’ll probably get about a third of one battery’s capacity from the solar panels on a sunny day,” Walworth says. “When he’s slowly following the dolphins, he could probably do it at 1 or 2 knots off the solar panels alone.”

Kitchell is working to help with fuel savings, too, by building Belafonte using resin infusion, a technique he’s been honing for the better part of his career. Nearly 20 years ago, Kitchell worked for a boat owner who believed the method might be the best way to get an ultralight boat and save on fuel. That owner did tourism runs from Key West to the Dry Tortugas and, like Belafonte’s owner, wanted to have an edge on the competition. If he burned less fuel, he could afford to make the run with even a handful of paying passengers when other boats had to cancel.

“It took us a little while, but we figured out epoxy infusion and started building boats that way,” Kitchell says. “I built him two 57-footers. It would depend on what speed we were running, but we were easily five times more efficient than the competition. We were burning 45 gallons a trip, there and back, running 120 miles. It’s incredible. I believe we put in 89 gallons every other day. It worked fabulously. We were getting close to 3 miles per gallon, carrying 49 people. Nobody does that.”

Kitchell was sold on epoxy infusion and made it his specialty. At the time he started with the process, other builders were using polyester and vinylester infusion, he says, but those processes use thinner resins. When people tried epoxy infusion, they often stumbled into expensive mistakes. “Epoxy is thicker,” he says. “You have to have a true vacuum — and that’s a lot trickier than it sounds. A lot of things can go wrong.”

With epoxy infusion, a traditional mold creates the shape of the boat. Workers lay up foam and cloth inside the mold and then put a bag over it. The bag is sealed, and there’s a hose for the epoxy that will be pumped into the sealed area. There’s also a hose for the exhaust going out. “That’s it,” Kitchell says. “It takes generally about an hour and a half to pull the epoxy into a hull, and then you let it sit.”

The process also saves on labor, he says. “With epoxy infusion, me and two guys can build a 72-foot hull in a week,” Kitchell says. “We lay up everything dry, we put it in a bag, and we displace the vacuum. You’re basically sucking the epoxy into the part. It’s clean. It doesn’t stink. You don’t get all messy.”

Belafonte could have been built other ways, Kitchell says, but epoxy infusion also helped to keep the owner’s costs down. “There are things you can do that are just as light, but they’re more expensive,” he says. “This is a more affordable way to build a light boat. I’d say you’re saving in the 30-percent range building it this way.”

Both the designer and builder are learning as they go. While they’ve worked on numerous multihulls together, as well as on separate projects, Belafonte is Kitchell’s first electric build and Walworth’s first electric design. “It’s neat for me because the house we built here on St. Croix is sort of the same technology, except we don’t have a generator,” Walworth says of his family home. “We have solar panels and a big battery bank. We’re completely off the grid.”

Walworth sees a lot of possibilities for electric boats going forward, in the recreational and commercial fields. The trick, he says, is finding uses that work with the limited capacity of today’s batteries. “It should be a growing field, I think, for the right application,” he says. “The batteries are getting better. The better capacity the batteries are, the less the generator has to run.”

Kitchell, meanwhile, says he is loving the problem-solving aspect of the custom build. Belafonte could have been finished faster, he says, but “we’re setting precedent here, so it takes time. I believe this design and the construction materials and methods will allow electric propulsion a major inroad into the powerboat world. I have a 54-foot mold in Costa Rica that I’d love to use to build an electric power cat from, as well … Maybe the right client will turn up.”

This article originally appeared in the June 2018 issue.