The history of weight shift controlled electric hydrofoils

Dear efoil community!

It is amazing to see all this innovation. We have now several hundred enthusiastic builders around the world sharing information here on this platform. This includes many companies building commercial efoil products, a lot of them are aiming for a launch in 2018. A lot of money is being invested here which is great and will help us all to move this world to sustainable, quiet, efficient and wakeless water transport.

I am writing this post because there are wrongfully issued patents to Prof. Jack W. Langelaan (1), (2). This will slow down innovation and growth of this fantastic new activity. Mr. Langelaan filed a patent about an electrically powered hydrofoil surfboard that is controlled by weight shift in 2013. Problem with that is that the claims in these patents were already well known at the time of filing, they were documented and published since Prof. Kuttenkeuler’s Evolo project in 2009.

Mr. Langelaan, I ask you to please cancel your patents. That would be the honorable and right thing to do in this situation. This would avoid unnecessary legal actions and not hold up fast innovation and growth of this sport. I give you the benefit of the doubt that you didn’t see the publications before filing. Many did see them. And I am sorry that the patent office didn’t do their job and research state of the art. My father worked as an examiner at the patent office for over 30 years, he was known to be a very thorough examiner and often came home upset when he noticed superficial research work by one of his colleagues. Oversight happens, but it doesn’t make it right.

The pioneers and real inventors are Team Evolo under Prof. Jakob Kuttenkeuler. I have been talking with Jakob and he gave me a lot of interesting background on this amazing work and he confirmed all the publications and dates. He is even considering a follow up project (Evolo 2) next year and I am already looking forward to that.

Project Evolo - Short Summary
The Evolo project was launched in August 2008 as a project in a course in the master program in Naval architecture at the Royal institute of technology, KTH, Stockholm, Sweden. A group of 14 students was given the task to conceive, design, implement and operate (CDIO) a new type of aquatic vehicle. In the project formulation it was specified that the vehicle should be able to carry one person at 15 knots, electric, environmentally sustainable, playful, silent, generate no wake. Controlled only by means of center of gravity movement. The students and teachers worked on the project for two semesters and arrived at Evolo which was tested and demonstrated in the spring of 2009. The technical work, findings and results were published online in 2009.

Project Evolo - Publications

I hope this information helps everyone, and especially Mr. Langelaan, to see that these patents are invalid. I am very passionate about the future of efoils and I want to help clear the path for innovation. A big driver of innovation are commercial efforts, as everywhere. I myself have no commercial interests but I am friends with many companies taking this to the market. I totally understand the importance of IP protection, I have a couple patents myself in other areas. It is these invalid fundamental claims on the very basic concepts of efoils that motivate me to engage. There will be many patents after this, smaller efoil innovations in different areas. That’s all fine. But these fundamental and wrongfully issued Langelaan patents need to go.

Please join me in congratulating Prof. Jakob Kuttenkeuler (he is also here on this forum) and his entire 2008/2009 Evolo team to this amazing Evolo project. We are looking forward to Evolo 2 next year.


Here some Evolo images:







The Evolo was way ahead of its time! Kudos!!!

According to Legal Zoom, a patent can be challenged at two different times:

Step 1

Obtain a copy of the original patent application from the USPTO website or other online source. Check its issue date to find out if you are eligible to apply for re-examination of the patent; you may apply for reexamination within one year of the patent’s issue date.

_ If you are threatened with a patent infringement lawsuit with respect to the patent, however, you have four months from that time to apply for reexamination, even if the patent was issued more than one year ago._

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Could not agree more Pacifimeister! :slight_smile: I have also looked into these applications, and came to a similar conclusion. I think the patent system is starting to be outdated (and seriously expensive) , open source development is much better!

Thank you for this overview!

I am very aware of the patent law. My father was a patent examiner :). I really hope we as the riders & builders community can help to put this to rest without anyone taking legal actions. I trust Mr. Langelaan is a good person with a sense for right and wrong who will decide to put this patent to rest once he knows the facts. Professors are role models for our society and I assume they operate under a strickt (faculty and personal) code of conduct. It’s that easy. And here we help to let everyone know the facts. We all have a big voice here. My logs show thousand of unregegistered users reading our posts about efoils. We are reaching many of the future customers/riders here. Let’s make sure the facts are out there and Langelaan (or any exclusive licensee) who just try to make money with what the Evolo team invented and published long ago are called out. Spread the word.


Hi all
I am one of the professors that with my students ran the Evolo project. I have been in contact with pacificmeister and am so happy that you all are engaged in this cool technology :slight_smile: As I also told pacificmeister, if there is any way in which I can help the process, just let me know!

Happy foiling!

/Jakob Kuttenkeuler


Hey Jakob,
From which country are you? Me and my team are looking for people who have experience in developing foils, motors and battery’s (actually everything which is happening on this forum). If you’re looking for a cool project for you and your students let me know!

We have played the patent lawsuit game in hydroflight. The sport has suffered because of it and declined. The holder of the wrongly issued patent could retract it.

We have gained far too much knowledge of the workings of the patent and legal system. We continue to produce, but have zero faith in the patent examination/issue process and also in the re-examination process. The legal process has cost the patent holders, (the guys that pushed out the “inventor” that filed it in the first place) more money in litigating it than they will ever see from it by a significant factor.

The dream of a patent is often turns out to be more of a curse.

If any body needs one to defend, we have a great law firm. :slight_smile:


Please all check out the interviews just posted on the patent topic. . A great step towards making everyone aware of the situation. Thanks Andreas!


Hello Merten,
thanks for this effort in collecting data and proof that the Patent filed by Mr. Langelaan is wrongfully issued. As we did not see any other projekt or proof of his invention it is furthermore obvios that he filed this patent based on knowledge reached by the former projects like the" Evolo" from Prof. Kuttenkeuler. As Prof. Kuttenkeuler is not connected to Prof. Langelaan it appears like a copy of research and invention.
We assume that this patent is not valid and will sooner or later be corrected. If Mr. Langelaan is not deleting his wrongfully patent himself, there will be a lot of lawsuit games about it in the future. And it will cost a lot of money even himself. I´m confident that he agrees on this sooner or later, allthough not expecting him to delete it instantly;-)
Thank`s Prof. Kuttenkeuler you and your team did the real invention back in 2009! and all our effort and future designs are based on this :+1:

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What bothers me here is that Liftboard, the makers of the eFoil is using lawyers to reach out to businesses to inform them that they need to license the idea.


I’ve done a lot of work with intellectual property. As hobbyists, no one is going to bother us for building a couple efoil boards for personal use. The only folks who need to worry about patents are folks who are trying to sell products commercially. Patent litigation is really expensive and time consuming, which is why many small business choose to license bogus patents rather than challenge them.

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Even if they don’t go after the hobbyists, it will impact everyone, including the DIY community. Several of the commercial efforts are considering to sell components to us makers, things that are really hard to source for us right now and not designed for our use case. Special motors, custom ESCs, BMS, remotes, etc… Many things that will make our efoils better and most important safer. Therefore we all need to educate the world and push against this bogus patent and clear the path for unhindered efoil innovation.


I totally agree with you - if there’s good prior art, then the 2013 patent is likely bogus. However, an issued patent is valid until challenged.

After a brief review of the two patents in question (the second is a continuation of the first patent), the patents cover the entire system (“a watercraft”). The drive train components we are discussing here could be used for many applications and are, by themselves, not covered by this patent. You could sell an entire drive train kit without violating these patents.

Trying to sell a complete efoil board or a complete efoil board kit commercially is a different story.

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FYI, here a patent discussion where Nick (Lift) chimes in. @David (Flite) posted a very good reply. I completely agree with David. Electric Hydrofoil patent? - #10 by Lift - eFoil from Lift Foils - eSurfboard, Jetboard & eFoil Forum

Nick says “the DIY community shall not fear”. In fact nobody should fear, the Langelaan pantents won’t hold up. I encourage everyone interested to read the 500 page Evolo report linked above to see the prior art for themselves. Easy with Google translate.


At last, with priority date from 2016-09-12, the JetFoiler / KaĂŻ Concept LLC patent from Don Montague et al :

Unexpected because it seems to be granted, a likely Austrian patent (Scubajet design ?) with priority date from 2017-06-21 (2 months after PacificMeister’s first video on YT) Electrically powered hydrofoil
Inventor : probably same as this other patent called Hydrofoil

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Each of these patents has a small “innovation” which is not yet part of the former patents.
Kai Concept uses “a throttle coupled to a top surface of the board” which is different from the remote control of Prof. Langelaans patent.
Also the first austrian patent claims that all electronics are in a capsule under water, which is then mounted to the mast, and the batteries are not in the board. The second patent about the hydrofoil only concerns the mounting of the wing to the keel fin.

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Curious, has anyone talked to Lift about licensing and fees yet?

Legendary. Thanks for sharing