One year has passed since I launched the autonomous boat OpenTransat that has attempted to cross the Atlantic Ocean and I wrote an article about it. The boat is lost in the ocean after being hit by crazy storms, but I didn't give up. Currently, I am working on the next sailboat with improved hardware and software and a more robust construction. The above picture is the design which is not final yet – it will be further improved in several aspects.

You see, it's based on interesting concept – a rigid wingsail that's adjusted by a "flap". It works much like an airplane wing. It's not something new – it has been used even on manned yachts:

3689723058?profile=originalHowever, I had no experience with this thing and I wasn't confident enough to believe it can work. Before going to spend a lot of time building a new 2-meter boat that will be designed for extreme ocean conditions, I've decided to build a 65-cm model to test and tweak the concept. Along the path, I've learned skills necessary to build strong composite parts.

3689723014?profile=originalThe carbon fiber/Kevlar hull is filled with a closed-cell polyurethane foam and painted with a special antifouling paint. This kind of paint doesn't give as smooth finish as a gelcoat or normal paint, but it prevents subaquatic organisms from attaching to the hull.

3689722974?profile=originalA waterproof servo is used for steering. As this is just a model for lake testing, the IP67 rating is acceptable here.

3689723023?profile=originalThe boat uses the same custom hardware and navigation software as the final design. The hardware is optimized for low power consumption and it includes plenty of sensors to provide more insight of what's happening with the boat. The program can be uploaded over Wifi which makes life a lot easier – I can debug and overwrite the program from the shore or motorboat. The battery provides enough power for 8 hours of continuous operation.

3689722995?profile=originalThe wingsail is made from a foam wrapped with carbon fiber.

And here's the finished boat:

3689723075?profile=originalCheck out the video of the boat sailing on a lake:

I'm happy to see it works!

You can follow the progress on this facebook page where I share all the details, attempts, mistakes and solutions:

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  • yrvind is something else.  Makes for pretty interesting reading if you are into sailing.  He invented an amazing sextant.

  • @James Pike Wow, I didn't know about this small manned boat. Thanks for sharing!

    I have been following another guy that crossed the Atlantic on a paddleboard-like boat this year.

  • Thanks for the reply.  Somehow I missed that first image.  Sounds like will give the ocean a fun/challenging thing to try and break.  You have probably run across this guy but he is building something similar for him to ride in (although he is the autopilot).  


  • @James Pike It's a prototype just to test the concept. The ocean-going boat will look much like the CAD model you see in the first picture (or the picture below) with some improvements. It has all the properties you suggested.3702405068?profile=original

    The sail size will be determined by finding the angle of heel at the maximum expected wind speed. It will be done by simulation. Regarding the material, I have been doing a lot of experiments by combining layers of carbon fiber, fiberglass and Kevlar and evaluating the properties of the result. I have found that the best composite is a combination of all three materials + a foam core. Carbon fiber provides rigidity while the outer layers of fiberglass and Kevlar will protect the hull from impacts and abrasion (shark teeth, collision with a vessel or icebergs).


    The only concern are GPS and Iridium antennas which will be located above the carbon fiber surface and far from the wingsail, not inside the hull. The antennas will look like the small dome you see next to the hatch. I think they should work with a 50% view to the sky.

    The boat has been tested on the Lake Neusiedl (Austria, Europe). I live in both Slovakia (Europe) and Canary Islands (Atlantic) depending on the season. :)

  • I love the project.  I would be inclined to change a few things just out of my own experience.  Put that steering servo in the hull.  1. IP67 might give you some confidence but with the different temperatures it will see and salt water I would protect that as the most critical component that it is.  2. Make the sail smaller.  You have a speed limit already by your short hull length.  Storms will make a mess of anything that looks like it could break.  3.  Put the gps in the hull and not in a mast.  Just isolate it from long wires and it will get great reception (test it in salt water though).  4. Make the hull and sail out of fibreglass so that it doesn't block the gps.  A boat that small should not need the strength of carbon fibre if it is built correctly.  Where abouts are you based?

    Best of luck


  • Hi Andy. I think this is great. Well done and thanks for sharing. Keep going - Im sure many will keep track of your progress. I know I will.

  • @Tobias Power is the main concern. The wingsail "flap" will be adjusted once per hour and the rudder will correct the heading every 5-10 seconds and even this would drain the batteries in 4-5 cloudy days.

  • Congratulations, I have read a lot about your previous trial and I'm looking forward for this one.

    Did you consider a Flettner rotor? Of course it need power but I would expect that it is far more resistent to damage by waves than the flat surface of a sail?!
  • 100KM

    I just want to say - this is SO COOL! Please keep at it and keep us posted!

  • @Evgeni Trenev The mast will be made from a thick carbon fiber tube. Both the mast and the keel will be connected to inner structure made from aluminum. I am not sure I can use ropes when the wing is free-rotating.

    You can see the keel with weight in the last picture (just above the video).

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