F4 is about passion – for the sport, speed, racing and quality. Creating the fastest, most stable and versatile foils on the market requires skill, constant R&D and countless hours of testing. Hydrofoils uniquely require the combination of 3D design, fluid dynamics, composites, and processes.

We have been fortunate to be able to work and innovate with some of the best riders and companies in the industry and drive the evolution of foiling across windsurfing, surfing, winging, and kitesurfing.

Based in Silicon Valley we followed in the footsteps of some of the most innovative and successful startups. We began with building prototypes in our garages, and over the course of the following few years we have won PWA races, speed records, and delivered countless hours of excitement and enjoyment for our customers.

We use cutting edge technology, manufacturing and the valuable feedback from our team riders and partners to deliver race proven premium products to our end users in all of the markets we serve.


F4 windsurf slalom Jenna Gibson The Story
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Customer Centric – Our customers are what we are here for.

Listen – Delivering products from the highest level of racing to consumers requires careful collaboration with you our end-users and listening and incorporating your feedback and needs into our products.

Make it happen – we know how valuable your time on the water is. And we promise you to do our best to make sure you have enjoyable time on the water with the most advanced product on the market.

The Environment – Our sport bring us in physical contact with nature. Our commitment is to protect it and enrich it so we can leave it better than we found it and allow future generations to enjoy it just as much as we do today.


In 2008 Al Mirel and Chris Radkowski – windsurfing and kitesurfing friends started F4 as a windsurfing fin company. Together they brought decades of experience with the sport, racing pedigree, engineering knowledge, Phd level math skills and endless enthusiasm and passion for the water sports.

The bug bit after the America’s Cup in San Francisco and hydrofoiling came to the scene in 2013. F4 were the pioneers that turned it from a dream into the fastest growing market and the phenomenon that spurred the endless innovation across wind winging, windsurf foiling, prone surfing, pump, downwind and more.

Laser focused – design the best hydrofoils possible for each application.

You can meet our core team on the beaches of San Francisco and at the Black Sea every day all season long.



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