Bob Woodruff’s solar sailboat

Bob Woodruff and Porter Thompson.

Bob Woodruff and Porter Thompson. – Stacey Rupolo

Bob Woodruff moves about the deck of his 24-foot Kittiwake sloop with an agility that defies his 82 years. “You could say I was born with a sailing gene,” says Mr. Woodruff. “I love the freedom aspect of sailing, the idea that you can sail into the wilderness because that’s truly what it is. You can see a whale — I recently saw a dozen dolphins. There’s something peaceful about sailing, something spiritual.”

But what Mr. Woodruff has never liked are those moments when there’s no wind or he’s bucking a foul tide and he has to turn on the engine — the ol’ stinkpot — that unholy alliance of noise and fumes that can take the proverbial wind out of his sails.

Mr. Woodruff is a lifelong conservationist. He’s a wildlife biologist by training, and spent 13 years with the Vineyard Conservation Society. So not only does an internal combustion engine betray the tranquility of a day on the water, burning fossil fuels tugs at his conscience as well.

Mr Woodruff has always dreamed of having solar panels on his house but it’s always proved cost prohibitive. When you’re 82 years old, a 20-year payback is not as attractive as it once was. But solar panels on a sailboat — hmm, he thought, now that could be interesting.

About five years ago Mr. Woodruff was sailing with his long-time crew, Porter Thompson of West Tisbury. Mr Thompson is a bit of a jack-of-all-trades and had in fact been living off the grid for about 40 years and has been installing solar power for decades.

“So Porter,” said Mr Woodruff while the two were out for a sail, “what would you think about going solar with this boat?” Mr. Woodruff recalls that Porter was being kind and experimental and he said that, sure, you could do that but there are realities. He asked to think about it and came up with a design that featured two, 18-inch by 18-inch solar panels that were installed on the topsides of the the boat. The panels fed two banks of 12-volt batteries — two batteries per bank — and those batteries in turn fed the electronics of the boat as well as powered the five-horse-power Torqeedo engine that was mounted in the stern well. Mr. Woodruff said that the Torqeedo is a German engine and it’s only about the size of a cantaloupe.

The only problem, according to Mr. Woodruff, was that the whole setup was “woefully inadequate.” So it was decided to add another 18-inch by 18-inch panel the next year; it turned out to be marginally more powerful, but the boat was still underpowered. When fully charged the engine would run for about one and a half to two hours at about four knots, but when fighting a tide or going for extended periods at full acceleration it could run for even less.

Which led to some embarrassing moments. On two occasions Mr. Woodruff found himself around middle ground with no wind and no power and being swept out to sea; he was forced  to call for a tow.

The problem was, much larger solar panels were needed and on a relatively small sailboat, deck space was at a premium. That’s when Mr. Woodruff had his big idea: Why not make the panels portable. This would allow him to add a pair of 20-inch by 40-inch panels — which in theory would produce plenty of power — but rather than installing them permanently on deck, they could remain topsides while being charged, then they could be stored below when the boat was in use.

Sure enough, the new rig is working like a charm. It’s been two years now and Mr. Woodruff told me on the phone last week that for the first time, they had to switch over to the second battery bank, so battery life has not been a problem. In fact, they really don’t know how long the batteries will last. Mr. Woodruff concedes that if he were going to be motor sailing for extended periods of time, this wouldn’t work so well, but for day trips where the engine is only used intermittently, it’s great.

I went out with Bob and Porter last week; it was Mr. Woodruff’s 30th sail of the year. It was a beautiful brisk fall afternoon and as we left the town dock in Tashmoo, we headed out toward the channel, preparing to set the mainsail and the only sound I heard was the waves splashing off the bow.

Mr. Woodruff called back, “Porter let’s give it a bit more juice and see what she’ll do.”

Mr. Thompson went back and adjusted the throttle. “We’re nearly full speed,” he said, “about 400 watts.”

At that point I could hear a slight hum coming from the engine and that was about it. We had shot up to almost hull speed, which is about eight knots.

Mr. Woodruff may just have stumbled onto something. Phil Hale, owner of Martha’s Vineyard Shipyard on Vineyard Haven Harbor said that at this time, he estimates that around 10 percent of boats in the area have some type of solar capacity. Many will have something to power the lights, radio, and the bilge pump, but to power an engine, especially in a sailboat, is another story. And those that have electric engines are most often charged by shore power.

“Electric is moving into the industry,” Mr. Hale said, “but in terms of boats whose sole motor  propulsion comes from electric motors, batteries [and solar panels] it’s his [Bob Woodruff’s] and one or two others.”

When Mr. Woodruff purchased his electric engine he bought a rehabbed Torqeedo Cruise 2.0 engine for about $2,000. Today that engine, new, costs a little less than $4,000. He spent about $700 on five solar panels and about $1,000 for four batteries. He also spent about $200 on wire and Mr. Thompson donated his services, installing the system for nothing. So Mr. Woodruff figures he probably spent around $4,000 total on the boat — money well spent as far as he’s concerned.

Right now, Mr. Woodruff sees that the big thing standing in the way of even greater acceptance of electric powered engines is developing greater battery storage capacity.

To which he says: “Come on, Elon Musk!”

This story by Geoff Currier, originally appeared on