About Us

Meanline Custom Fins designs, develops, and manufactures premium race foils for a variety of ocean sports, including kiting, SUP, and windsurfing.

Headquartered in Maui, Hawaii, Meanline conducts ongoing research and development in the most extreme conditions in the world with a team of truly motivated, passionate, and experienced water sports professionals.

This process of continuous improvement involves the latest manufacturing practices with the goal of achieving a real performance advantage on the water, an advantage that we can rapidly transfer into the hands of our clients.

Our purpose is to bring the best possible product direct to our customers.

We are driven to bring our clients, who share our deep passion for water sports, the performance edge they desire.


Our History

Meanline is owned and operated by Kai Hopf, a true water sports industry professional.

Kai’s passion for ocean sports began over 4 decades ago as a former slalom racer and wave sailor.

Kai started his own Board and sail brand whilst still a teenager.

Kai joined North Sails, Ltd, in 1992 where for over 20 years he’s led the company’s sail design and development efforts.

Kai then partnered with  System B fins, where together with Bernie Brandstaetter, an early pioneer of CNC foils, Kai began developing prototype fins that quickly set the standard for the industry, including F2, Mistral, and Fanatic.

At Meanline, Kai’s commitment to superior fin design and performance reached a new height with the decision to move all operations to Maui.

The move to Maui gives Meanline unparalleled advantages in the marketplace in terms of testing and development, manufacturing and quality control, and even distribution and customer support, allowing us to serve our clients to the highest possible standard. According to Kai, “You just couldn’t ever get to this level in Asia.”

On Maui, we can control every aspect of the business. We design new foils specifically around the needs of our clients, manufacture those foils with people who are passionate about their work and are themselves water enthusiasts, test those foils on the water with a world-champion stacked team of riders, and then rapidly distribute out to our Clients, who provide us immediate feedback that kick starts the process all over again.

Maui is the epicenter of our sport. Here we have the best of everything, not just the conditions, but also the people and manufacturing capability. For example, with Mike Rutherfordstorm heading up our manufacturing, we are even better positioned. Mike’s experience working under such industry luminaries as Peter Thommen and Mark Nelson is invaluable and he gives us the critical mass to really make an impact in the market. His passion for the craft is evident in every fin that goes out the door. 

Our Team

Kai Hopf, designer:

“I’ve devoted a lifetime to the water. First, as a former world-class professional windsurfer, then later as a sail and fin designer.  My days now cycle between the office, the workshop, and the water, at each phase interacting with my team, my fins, and my customers, pushing my product capability to the next level.”


Mike Rutherfordstorm, manufacturing:

“Composite manufacturing has been my life, ever since moving here from Canada. I’m industry-taught, and taught well. I’ve been instrumentally involved in the high end building of custom layouts from the ground up, working on everything from boards to fins to even ocean skies.”


Jimmy Diaz, Peter Slate, Drew Farrier, Alex Aguera, team riders/testers:

Our team riders share not just a passion but also multiple world championships between them and they never miss an opportunity to take our products to their limits and beyond. This collective feedback is crucial and helps us deliver to our Clients foils that not only work, but set entirely new standards for the sport.