Wetwing

The WetWing: Jochen Ewert's Masterpiece in Human-Powered Hydrofoil Design

The WetWing, designed by Bavarian engineer Jochen Ewert, is an extraordinary prototype that showcases the cutting-edge potential of human-powered hydrofoils. What sets the WetWing apart is its versatility: with interchangeable wings, it excels across a variety of disciplines, from short sprints to long-distance endurance rides, and even slalom races. At this year’s championships, the WetWing proved its dominance by winning the slalom event, delivering blazing speeds over 100 meters, and astonishing spectators with an incredible 7-kilometer flight solely on its wing.

But that’s only part of the story. Jochen Ewert himself has achieved feats that underscore the WetWing’s remarkable capabilities:

---

Some Remarks from the Inventor, Jochen Ewert:

"Hi,
I would like to mention that my longest flight with the WetWing was 20km without touching the water (1 hour 55 minutes, on Lake Starnberg in Bavaria, from the south end to the north end). My longest trip was 30km in 3 hours 15 minutes, including a 15-minute break (staying on the boat but floating, not flying)."

---

Ewert’s WetWing is not just a high-performance machine—it’s a true labor of love, meticulously designed and built as a one-of-a-kind prototype. Unfortunately for enthusiasts, there’s only one WetWing in existence, and Ewert has no plans to mass-produce it. In his own words:

---

"Hi all who are interested in buying or building another WetWing,
This is Jochen Ewert again.
I am afraid that I have to disappoint you, but the WetWing is a prototype built by me, and there is only one unit, which I want to keep for myself. Also, I never found the time to create detailed plans for it, and some parts would be quite difficult to replicate.

At least, here is some info how the different parts of the boat are made:

Framework: Aluminum tubes, carbon fibre tubes, steel cables (very simple, very light, very stiff; I consider it as a good design). Handle bar is standard bicycle part.

Floats: Fibre reinforced polyurethane (as used for life vests in commercial aircraft; needs experience to work with; work not carried out by me but by someone in northern Germany who made them in his garage according to my sketch. I consider it as a good but extreme design: 0.7 kg per float including fixings! Volume 90 liters each.)

Seat: Styrofoam shaped by hand, coated with glass fibre reinforced plastics (epoxy). The shape is optimized for my body. The strength of the seat is optimized for my weight and muscle power (both rather low). Good ergonomics: A 10mm layer of soft foam is enough to stay hours on the boat without pain. Potential for improvement: lighter foam or honeycomb, carbon fibre instead of glass fibre.

Strut (that is the surface piercing part that connects the framework with the wing): Aluminum skeleton, styrofoam coated with glass fibre reinforced plastics. Big potential for improvement: integral carbon fibre (CRP) design, much slender shape.

Wing: Carved cedar wood covered with CRP. Big potential for improvement (weight and performance): integral CRP, greater aspect ratio.

Front foil: CRP, laminated in CNC milled mould. Expensive; good design.

Front strut and surface follower: original parts from Trampofoil (see link on this website)

Drive train: Bicycle serial parts (pedals, cranks, bottom bracket), custom made chain ring (chain pitch 6mm: very light and smooth running), custom made drive train in the strut (second chain, also 6mm chain, Moebius band twisted design).

Propeller: CRP laminated in mould by Theo Schmid of Switzerland (as long ago as 1980's). Seems to be very efficient.

Some general remarks:

The boat has to be designed to your weight and power output. A "one-size-fits-all" design for a human powered hydrofoil is far below optimum. It would work but it's less fun.

If you want to use the boat for long distance rides (10 - 20km), the weight of the boat and your weight are crucial. If the weight is high, you need high power output. In my case, boat plus rider, life vest and filled drinking bottle weigh 75 kg (!).

Regards, Jochen Ewert

---

Jochen Ewert’s WetWing is a testament to both his engineering genius and the limitless possibilities of human-powered transportation. Though it remains a singular creation, its legacy inspires anyone interested in the future of hydrofoil technology and sustainable personal transport.