Fin Maker Scales Up Production

“Mastercam is smooth. It has just about everything I need, and it talks so well with other programs I use routinely, like Illustrator, Excel, and SOLIDWORKS. Mastercam is also vast. I am constantly learning how to do new things in it. It never stops.”
~ Curtis Hesselgrave, Designer and Owner of Curtis Fins, Carlsbad, CA

Curtis Hesselgrave’s designs and manufactures fins that are used by participants in the Lüderitz Speed Challenge, an event that demonstrates just how fast a sail powered vessel can travel. Over the years, Curtis has supplied fins for 3 world record setters (not all at Lüderitz). That is more than any other designer.
His company, C&M Engineering, owns and manufactures the Curtis Fins line of fins that are used on surfboards, sailboards, stand up paddleboards, and kiteboards (both original and replacement products). He has been designing fins for more than three decades. He participates in speed sailing for the love of the sport and also to prove a point: “Fin designs make a big difference in both the speed and performance of a surf- or sail-powered board.”
For the longest time, Curtis made hand models of his designs by cutting blanks of composite material with an automotive grinder. Today, he may haul out his grinder once in a while, but mostly it is gathering dust on the shelf. Instead, he creates his designs electronically with a CAD/CAM system that he has been relying on with increasing frequency since the mid ‘90s.
Curtis uses Mastercam X4 Mill and Design software because it provides a single computer environment from which he can create fin designs and then move immediately in to make toolpaths for his Haas CNC TM2 toolroom mill. The mill can be used to cut fins nested in long blanks of fiberglass or composite material or to cut tooling components if the fins are to be molded.
What he values most is the fact that Mastercam allows him to go as deep into the program as he needs to fine-tune his designs to get the very best shape for the fin’s surface area. This is the key to achieving exceptional speed and performance—something professional and amateur surfers notice as soon as they try out a board equipped with Curtis Fins.
Curtis uses a unique combination of software products to create his designs, including Adobe Illustrator, Microsoft Excel spreadsheets for storing fin design data points, and SOLIDWORKS for quickly knocking off fin bases. Files from these programs are all easily imported into Mastercam.
In recent years, Curtis has set up a very specialized electronic environment in Mastercam for creating his designs and CNC programs. All the unique tools he uses routinely are assembled in toolbars right next to the fin model he is working on. He can get to anything he needs with just one mouse click. An extensive library of fin shapes allows him to associate operations from designs that were created previously. “What used to take me hours,” he said, “I can now do in about 30 minutes.”

It’s a good thing too because there are dozens of Curtis Fins models, and each model has many different sizes. “Each fin size is unique,” he said. “None of them can be scaled up or down from a previous size. So my unique tool set allows me to quickly clean up profiles I get from my customers and create the toolpaths I need to manufacture them.
“This capability has become increasingly important to me because board sports enthusiasts are really catching on to the importance of fin design. So our company has adopted a new distribution model that will make our fins available for a wider range of board types and to a more diverse customer base. Our volume is going to expand significantly and we would not be able to keep pace without our unique Mastercam capabilities.”
Note: In October 2010, Rob Douglas of Martha’s Vineyard, Massachusetts, USA, eclipsed the world 50 meter speed sailing record by traveling at an average speed of 55.65 knots(subject to official ratification by the ISAF/World Sailing Speed Record Council). His kiteboard, equipped with custom-made aluminum Curtis Fins. (See the YouTube video at

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