Monday, March 10, 2014


Finally somebody is working actively in what seems to be an obvious way to generate electric electricity on sailboats: Photo-voltaic sails. Till now the technology did not allow for panels flexible enough to allow that but on last years the technology has evolved a lot. It is already possible and it will not be expensive in the future. At least a sail manufacturer is working already actively on that, the UKsails France branch.

They say about that :

"SolarClothSystem ® was developed to achieve the integration of a photovoltaic  high efficiency film from the latest generation (14 %)  in products for outdoor and water sports : mainsail , lazy bag , bimini, Sprayhood...
SolarClothSystem relies on the experience and technology of offshore Titanium sails, developed by the UK Sails of Mandelieu (France),  for nearly ten years.
This new film is active with natural or artificial light directly or indirectly . It remains active on cloudy days as well as with low light . These characteristics are particularly suited to various situations encountered while navigating.
The thin PHV film ( 65 microns, DSSC type) is made ​​in the USA . The integration is carried out in France in Mandelieu -La Napoule (patent pending) .
The cells are either integrated into the layers of a new sail membrane type or added on sails, new or used , gluing and sewing on woven materials, such as Dacron or Spectra . The flexible film allows the mainsail to be rolled on the boom .

The solar energy is transported by an integrated flexible circuit through the sail's luff and then to the foot of the mast . A small electronic controller is installed inside the boat to control the battery charging.

The photovoltaic mainsail aims to ensure energy independence while the boat is sailing . It will be enough for the consumption needs of a 40 foot boat equipped with : LED lights, fridge (well insulated), water pumps, conventional electronics (excluding Automatic pilot). The photovoltaic surface necessary in the Mediterranean use ( ref. Marseille ) will be approximately 3 m2 on the summer months (290 Watts / hour maximum period of strong sunlight ) and regarding the North of Europe ( ref. Hamburg) about 4 m2 for the same period."

That sounds like music to my ears and it is almost too good to be true, I hope they can manage a decent prize. It is not really necessary to use sails. If used on the top of a Bimini and a sprayhood those 3 m2 are easily reached (on a 40ft boat) and 290W an hour is just huge for non intrusive solar panels. With that plus the use of those panels on the sails the energy generated would be enough for all, including autopilot. With that my engine will start to rust :-) since I use it most to charge the batteries while cruising.


What would you do on the hook? just leave your sail flogging in the wind? I obviously like the ability to create more energy, but it doesn't solve the issue of when you're not sailing. 

Hi OPC! That was not only about panels on the sails. On the article it was mentioned the possibility of using that on the top of the Bimini, Sprayhood and lazy bag. Only that area on a 40ft boat would have the 3 m2 (290 W/hour) that they consider enough for the needs of a 40ft sailboat (except autopilot). On anchorage the needs will be smaller (no navigation lights).

But really the most interesting future of this technology is to be able to make sails and tissues entirely photovoltaic even if with a lesser efficiency than the  announced 14%. Even with an efficiency 3 times smaller the 110sqm of my sails would produce something like 3200W/hour. Some hours of sailing each day while cruising would be enough to have the batteries fully charged, assuming you are using AGM batteries able to store all that load in a short time.

Typically, flexible or "soft" solar panels are often placed on top of the sprayhood on many cruising boats, as well as on the coachroof and bimini - i.e., wherever there is a flat surface where such panels may be placed (Mini 6.5's do this, for example). These soft panels are supplemented by more conventional "solid" or "rigid" panels mounted on the transom in one form or another.

The primary beneficiaries of incorporating photovoltaic cells into the sails themselves would be racing boats which have their sails up for very extended periods - e.g., ocean racers like the IMOCA 60s, VOR 65s, Mini 6.5s, Classe 40s, etc. The benefits are significant when you factor in reduced weight from carrying less fuel, reduced windage from fixed aft-mounted panels and windvanes, reduced drag from hydrogenerators, etc. Imagine, for example, photovoltaics in the massive mainsail and gennaker of an IMOCA 60 or MOD 70 - that's a lot of potential power generation. If sailmakers are able to implement the technology while preserving the performance characteristics and longevity of the sails, it will be a tremendous improvement. Looking forward to seeing how this evolves.

Hi Pelicano!I know about soft solar panels. I even have one on my boat :-) But their "softness" is relative. They are flexible but it is not about that we are talking about but about a fabric, an integrated "cloth" that has photo-voltaic properties, not something you put over a bimini or a sprayhood, but the Sprayhood or the bimini itself made out of photovoltaic cloth. If you can do that for sail cloth you can do it for any cloth. We are talking about this: and it seems it is already a reality.

Yes, probably that is going to be used first on long distance racers, or maybe not depending on how much will affect the sail in its sail performances. Even a very small loss can be critical for a racing boat but irrelevant for a cruising boat.
 You see it on a racing boat, me that I am a long range cruiser, in a sense I cruise non stop for 3 or 4 months, cannot wait to have that stuff in my boat. I sail a lot and I use mostly the engine to charge the batteries. Not needing to use the engine would not only save a lot of diesel as it would make it last longer, need less maintenance, give me a more peaceful time and most of all, increase the boat autonomy. The engine is good to charge the batteries to 85% but  AGM batteries need to be charged at 100% from time to time. 

I sail about 6 hours a day while cruising and I cruise in the summer so I believe that sails woven with solar cells could produce enough energy to full charge the batteries. The smaller surfaces on the Bimini, Sprayhood and lazybag would be enough to maintain them with enough charge for the periods on anchorage. It seems perfect to me. I too look forward to see how this turn out, or better, when It will turn out:-) I hope I will still be around ;-)

Paulo - Yes, that was how I understood it - i.e., photovoltaics incorporated into the sail cloth itself. However, I probably did not express the distinction clearly, in my transition from "soft" or "flexible" solar panels and the new direction detailed in the link you provided. Indeed, if you think about it, once the capability exists to incorporate photovoltaics into cloth, there is literally nothing that might not be put to service generating power - e.g., cockpit cushions, sunbathing towels (on the foredeck or aft swimming platform). Even in foul weather gear - consider how much time a singlehanded skipper may spend in the cockpit of his/her Mini 6.5 :)
All exaggeration aside, this is a major technological breakthrough in many ways, and should contribute significantly to making sailing an even "greener" activity (not to mention making moorings much quieter - less diesel generator / windvane noise).

Well....I agree!!! :-)


  1. what would you do on the hook? just leave your sail flogging in the wind? I obviously like the ability to create more energy, but it doesn't solve the issue of when you're not sailing. hmmm opc

  2. I am always searching for informative information like this. Thanks for sharing with power

  3. Could wind power not be harnessed instead of solar power?

    1. It is what allows us to sail ;-) but in what regards electricity production, out of the wind generators, I do not see how. Have you any ideas?

  4. when on the hook use your wind generators.

  5. I don't sail but this idea interests me. Why couldn't a turbine of some description be fitted to the underside or even integrated into the keel to add to energy produced

  6. That is called an hydrogenerator and many oceanic sailboats use them. On the Vendee Globe, the non stop sailing race around the world most boats have two. They are expensive, with a price around 4/5000 euros.