1216 Nautical Miles to Alaska or a Scenic Ride on the Hudson River

One of Solar Sal’s boats, The Wayward Sun, travels through the Inside Passage to Alaska entirely powered by the sun. (Courtesy photo)

George Harvey

Over the years, Green Energy Times has published at least four articles on Solar Sal, a solar-powered boat company and the boats it makes. The most recent of them is “The Solar Sal 24,” in our issue of August, 2022 (bit.ly/SolarSal24). When we first published the article, the solar-powered boat was a concept that may have seemed just a bit too bizarre to some people. After all, solar power and batteries were both rather expensive. But it has hung on for a reason: it is just too good to go away.

Solar Sal was developed by David Borton, who retired in 2014 from teaching engineering at Rensselaer Polytechnic Institute after 33 years. In his retirement, he founded Sustainable Energy Systems, and Solar Sal Boats, which is a subsidiary of that company. But the company has done a lot in those years.

Solar Sal Boats is not just a boat maker. While Borton has manufactured boats, the boats whose power systems it designs are most often actually built by other companies. For example, a 44-foot boat by marine architect Dave Gerr, the first solar-powered boat ever inspected by the Coast Guard, had its power system designed by Solar Sal. It operates to carry up to 30 passengers on the Hudson River. It has a 10-kilowatt (kW) Torqeedo outboard motor and 5-kW of panels on the roof. At the time it was submitted to the Coast Guard for review, they did not allow lithium-ion batteries on boats, but they have changed that policy.

Most of the Solar Sal boats are built on the East Coast, but Dave Borton introduced them to Sam Devlin, who builds boats on the West Coast. He built Wayward Sun, which was originally conceived as a lake boat, that was in a boat show in 2019. It has 1,700 watts of solar panels on the roof, 21-kW hours of storage in its battery, and the motor is 4-kW, enough to give it a top speed of about 6.5 knots, close to 7.5 land miles per hour.

We might do well to mention what that boat has done. Dave Borton and his son, Alex traveled on the Inside Passage to Alaska aboard Wayward Sun, entirely powered by the sun. Even with overcast skies, the boat was able to move at about 4 knots using current ‘cloud shine’. At the time, Canada was still under strict Covid restrictions, and the boat did not stop, except at night, when it anchored, or to buy supplies, which were delivered. The two men were not allowed to go ashore until they got to Alaska.

The boat used just sunshine, and the battery, charged by sunshine, was used just to even things out. Most of the trip was overcast, but the boat was normally run just on the light that got through on the cloudy days. So, the distance the boat could travel was largely a function of speed, and its occupants adjusted its speed to allow continuous operation.

The trip was from Bellingham, Washington, to Juneau, with a diversion to Glacier Bay. The distance traveled was 1216 nautical miles (1400 statute miles). This is believed, almost certainly, to be the first voyage between Washington and Alaska powered entirely by sunshine.

We should not end this story without pointing out that solar-powered boats, and more often electric boats, are becoming much more common than they ever had been in the past. Small electric boats can be purchased fairly easily. And today, one of Solar Sal’s boats is carrying passengers on the Hudson River. Passenger ferries are getting to be common in some parts of the world. We have news of the first tugboat to be used in the United States, which is impressive, because tugboats can have enormous power demands, proving that electric motors are strong.

Read more on Solar Sal’s website, which is www.solarsal.solar.