Digital design technology is transforming transportation, from aircraft and auto parts to military and rescue watercraft. Now, this technology of tomorrow is tackling Olympic competitive sailing—at least on the side of the official US Sailing team.
Richard Didham—a design/analysis engineer for US Olympic Sailing Innovation, Research and Development—hopes to wring every possible performance improvement out of the many variables that affect Olympic sailing ahead of the 2020 Summer Games in Tokyo.
Working at Autodesk Technology Centers in San Francisco and Boston, as well as US Sailing’s own FAST USA technology center, Didham needs to steer the huge number of moving parts in this venture toward a single endpoint. “The three most important factors in sailing are boat speed, boat speed, and boat speed,” Didham says. “Many factors influence an athlete’s performance in a race, but if their boat is faster, it can make up for mistakes in other areas.”
In the Venn diagram of boat speed, the confluence of variables includes racing environment, tactics, human factors, coaching, and—crucially for Didham and his team—sailing equipment.
Capturing the Real World
The Olympic sport of sailing isn’t what you expect if you’ve seen any of the iconic races (or aftershave commercials) featuring teams of up to 10 sailors who form a well-oiled machine aboard a large yacht.
Olympic sailing has one, sometimes two, crew members. The craft is much smaller than a standard yacht, with strict design and manufacturing constraints. “Everyone is supposed to have the same basic equipment to race with,” Didham says. “It makes it a lot less a competition of design and more one of athletic sailing ability.”
That leaves extremely narrow bands for designers to prototype and manufacture components, exploiting “really small” differences within the rules for marginal gains above the competition. To do that, US Sailing has invested heavily in complete system modeling—of not only the craft and performance but also the entire race itself.
The team’s data-acquisition platform, or DAP (from provider SAP), is a three-stage quantitative measurement tool that combines data generated by the athletes, the equipment, and deep video analysis of the race and venue. Competitive sailing is itself a difficult-to-standardize sport, as it relies on environmental factors such as wind and water. To compensate, the DAP incorporates everything from tactical analysis and equipment performance to each sailor’s athleticism and style. This data can all be folded into a simulated virtual-reality representation of the race: an HD model for athletes, coaches, and designers to scrutinize.
Sailors and engineers may have little control over the many variables, but some components can still be optimized to respond to them. “We want to profile anything we can’t change to the best of our abilities,” Didham says. “You can have lots of breeze, no breeze, a very choppy sea state, a really flat sea state. Currents vary from one venue to the next and with tides depending on time of day. It can be really difficult to know how to race in the specific set of conditions.”
Being forearmed with that knowledge lets the team pair the athlete with the environmental conditions, coming up with the best possible vessel design to take advantage of both.
The Test Case
To that end, Didham and his team turned to a Moth Class boat, a “hydrofoiling dinghy,” as its prototyping vessel. The Moth uses an underside wing, called a hydrofoil (or just “foil,” which also refers to this type of boat), that lifts the hull out of the water . The Moth isn’t the craft that will compete in the Olympics but rather a proof of concept—the resulting R&D insights will inform the optimum design for production. But building prototypes with the Moth frees the team to “test out different ideas without having to get caught up inside these intricate little details,” Didham says.
Designing, prototyping, and manufacturing the Moth’s hydrofoil encompassed this project, addressing two major areas of inquiry: optimum design for dynamic and efficient travel through the water and the material science of carbon fiber–reinforced manufacture. (Most of the equipment inside Olympic Sailing are carbon fiber–reinforced composites, according to Didham.) Put in simpler terms: “All we want is the maximum lift versus drag,” Didham says.
The team used complex computational fluid dynamics (CFD) software, finely modeling the way bodies of water move to come up with hydrofoil profiles. Numeric values for the bluntness of the hydrofoil wing’s leading edge, values of its maximum thickness, the sharpness of the trailing edge, and more are programmed into the algorithm, and a new design is generated automatically. “All we have to do is type in a few numbers,” Didham says.
“We can create and analyze every single possible foil shape in the world, look at the graphs, and simply pick the right one,” he continues. This narrows the field; they choose the top few shapes and then run another set of analyses. Once this process is repeated, the disparity in different shapes’ performance practically disappears.
“The differences in performance start to converge, and you just stop the algorithm—you have your optimum foil,” Didham says. “Once we have our optimum foil shape, we’re then looking to bring that into CAD and create a solid model of the body.”
The data is sent to the integrated CAD/CAM environment of Autodesk Fusion 360 to model—an environment in which you can make changes and specify the machine processes, preparing it for CNC machining.
Working on a midsize CNC machine at the Autodesk Technology Center in San Francisco yielded a mold that was “95 or 99 percent of the way there,” Didham says—and the next step was determining how to make the final parts. Coming up with the best way to enmesh sheets of carbon fiber is not straightforward; a program such as Autodesk TruComposites helps determine the layups of carbon fiber along with the manufacturing materials to achieve the mechanical properties of thickness, tensile strength, and other factors necessary for the composite’s strength.
The final step, fabricating the hydrofoil, uses a process to transfer resin into the carbon fiber, creating a part with uniform mechanical properties. The optimized design—what the team hopes to be the best-performing, single-person carbon-fiber hydrofoil—can then be polished and ready to sail.
“The hydrofoil project was successful in a few, not strictly quantitative ways,” Didham says. “It let us explore our manufacturing capabilities with composites and our analysis capabilities for designing foil shapes for boats. It was great to use Fusion 360 and TruComposites, which were completely new to us. Using the CFD code, we achieved the maximum lift versus drag for the specific design constraints of the hydrofoil, and as you refine your skill set in these areas of engineering, you’ll produce better results.”
The View From Here
With the design insights from the Moth hydrofoil, the team will refine the aptly named Finn rudder, which shares similar properties, for competition. To be ready for the 2020 Games, the Finn has to improve on current designs and also be customizable to different athletes. “We can improve in a few key areas that will just give general better performance among a variety of conditions,” Didham says.
It also has to produce low drag and remain structurally sound while racing, all within the Olympics’ design and manufacturing rules. This is where the DAP data becomes crucial: To build a better foil, the team will need reliable data to understand how different athletes and design considerations could work together.
With so much at stake, the race to find any possible advantage is worth it. And as US Sailing is proving, digital design is part of the hefty toolkit needed to build the perfect racing sailer.