Solar Sailing - Sailors for the Sea

Solar Sailing

 August 18, 2016  | By: Oceana

Photo: J-Boats

The wind is solar-powered. Quite literally, wind is convection currents created by sun heating the earth. Now 21st century solar technology allows sailors to harness the sun, as well as the wind, to move us through the ocean. The J-88 day sailor is a leading example of a growing trend in integrating alternative energy technology into boatbuilding. We recently had the pleasure of test-driving the J-88 in Miami. 

Driving the OceanVolt Electric Drive

Imagine having a quiet conversation on board when powering to the marina after a relaxing day sail, instead of revving up the internal combustion engine. No more choking on diesel exhaust going downwind, no more gasoline fumes in the bilge, no more fuel dock runs. The J-88’s solar package, built around an OceanVolt SD6 6kW 48vdc propulsion system and UK Sailmakers SolarClothSystem® solar panels on the mainsail and bimini, opened our eyes to those possibilities. With these innovations, fossil fuel propulsion may soon be a relic for “classic boat” aficionados.

The OceanVolt drive is indeed quiet. While not Hunt for Red October silent, the electric drive is a huge improvement over the diesel experience.  When motoring at five knots, we had to ask whether the electric drive was on. Down below one can hear the drive humming when engaged, and there is of course the mechanical churning of the prop thru the water, but the contrast with diesel systems was striking. Perhaps the most surprising aspect of the electric drive was the brawny torque and “bite” on the water when accelerating or shifting into reverse. The electric drive ramps seamlessly from a standstill to full power like a Tesla Model S, noticeably more smoothly than a mechanical drive system.

Photo: J-Boats


Minimizing our Environmental Impact

Sailing is already relatively clean, but the solar sailing package reduces the remaining environmental footprint dramatically.  As stewards of the ocean, solar sailing is an inspiring opportunity to eliminate fumes from getting in the way of enjoying nature, make fuel spills a vestige of the past, and banish greenhouse gases that worsen climate change and ocean acidification.

Solar Panels in Sails

The electric drive is powered by an integrated system of Valence U24 lithium phosphate batteries and 600W solar panels. The solar panels are laminated right into the mylar sailcloth mainsail, allowing the batteries to charges while sailing, and another array of panels are sewn into the bimini for charging while at anchor or dockside. In the J-88 configuration that we sailed, the mainsail had 9 solar panels on each side, and the bimini has a zip-in 6-panel layout.  The thin-film solar panels are as flexible as the sail itself, shape smoothly when hoisted and flake easily over the boom (see photo). The panels can be placed in the lower third of the main for racing configuration, or in the mid-third for a cruising main to allow for reefing while keeping the panels in the sun. Thin wires run down the luff along the mast into battery bank, similar to wiring from wind instrumentation.

Photo: Stuart B Photography

More ways to Power Up

Of course, the battery system can also be charged conventionally with shore power with a 5-6 hour recharge time from empty. But apart from the solar charging, the electric drive can actually power itself – if you have enough wind to cruise at 6-7 knots under sail, the prop will spin backwards to charge the batteries, serving as an underwater generator. 

Practical Sailing

Previously, the challenge of solar-electric propulsion has been range, but this new technology is a breakthrough. On a full-charge there is enough battery power to motor up to 20 nautical miles with no sail or with solar power support depending on wind and sea state. In theory, on a sunny day, with the solar panels charging and 4 knots of wind for the sails, the J-88 can motor-sail at a cruising speed of 5 knots all day long!  This estimate is based on perfect conditions, but considering even gas or diesel runs out eventually, the range is pretty impressive. We motored in Miami harbor for almost an hour and the battery charge scantly dropped from 93% charge to 86% with no solar charging.  In any event, most recreational sailing is coastal and easily within the electric drive’s range. J-Boats and other manufacturers are also looking at adapting highly efficient and clean fuel cell technology (which generates electricity from propane or natural gas) for sailors who need blue water cruising range.

Photo: J-Boats

The electric propulsion system is fully integrated with high-tech power draw monitoring and other data systems to allow the crew to manage charging and propulsion options.

The solar sailing package, being innovative technology, does cost more than a conventional diesel engine, adding 10 to 15% to the purchase price for a full solar sailing package.  But the cost is coming down rapidly and there are savings that one would not think of at first, such as not needing a muffler or fossil fuel storage system, and of course the savings (both financial and convenience) from not needing to purchase fuel.

The J-88 itself is a sporty day sailor with a nice mix of ease of sailing and race-ready performance — but others will write about that.  What gets us excited as a Sailors for Sea board member and cruising sailors is J-Boat’s integration of several cutting-edge products creating a green and clean energy package.  For more information, visit

Check out Sailors for the Sea’s Green Boating Guide for more information on how to go green on your boat. Download your free copy by clicking here.

Max Williamson serves on the Board of Directors of Sailors for the Sea and boats on the Potomac River and coastal Maine with spouse Leslie and dog Talisker.