Be­la­fonte, a 35-foot power cat un­der con­struc­tion in Cal­i­for­nia, is likely the first Coast Guard-in­spected pas­sen­ger ves­sel with elec­tric power.

Soundings - - Contents - By Kim Kavin

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. 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 Guardinspected 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.

“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 snorkel-

ing. “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.”

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 bat­ter- ies 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.”

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.

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

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

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