Engineering students compete with concrete canoe
Pictured above and to the right are members of the 2017 Concrete Canoe Team at UW-Platteville.
PLATTEVILLE, Wis. – Picture a chunk of concrete. Just for the sake of this exercise, let’s make it about the size of a softball.
Now imagine that you stand on the shores of a vast and sparkling lake. You haul back and throw the concrete ball as far as you can into the water. The ball … floats?
Welcome to Concrete Canoe. Every year, thousands of engineering students from schools across the country compete to build floating, maneuverable, fast canoes from the world’s least seaworthy material. Each design takes months to conceive, create and cast. Along the way, there are hundreds of opportunities for disaster. Finally, there is the risk that you – and your friends – will get very, very wet. It’s the kind of challenge civil engineers love.
“There are no professors in the room when we’re making our canoe,” said Taylor Chittick, a civil engineering major from Marion, Iowa, now entering his fifth year at UW-Platteville. “The effort is one hundred percent student led.” Chittick, the team captain of Concrete Canoe, led his team to the American Society of Civil Engineers National Concrete Canoe Competition, held in San Diego, California. Twenty-five teams entered this year’s NCCC, which was composed of four main event types: a design paper authored by the team, an oral presentation about the canoe, final product judging, and then a grueling series of races, including men’s and women’s sprint, men’s and women’s endurance, and coed sprint. Nail-biting as the races are, they represent only a tiny fraction of the time and effort that goes into creating a concrete canoe.
“We spend the first three months of the school year building the mix we’re going to use,” Chittick reported. “We want to make it as light as possible while also being able to bear the weight of the paddlers.” Finding the right kind of concrete means testing a lot of different aggregates. “We test a lot of materials ideas,” says Dominic Cypher, a fifth-year civil engineering student from Mayville, Wisconsin. “Every year we use small glass bubbles, but due to a new rule change we must incorporate a certain amount of natural aggregate. This change means we had to add a percentage of pumice to our mix along with the glass bubbles we already have. You use different materials every year, and you adjust those materials based on how you perform.”
The concrete mixture must meet a challenging set of contradictory needs: it must be strong, yet lightweight. “There are all kinds of different materials, and we go around and feel the different finishes [at competition],” Cypher said. “Some mixes are heavier and super strong, some are lighter and built for racing. There are some schools that build a couple of canoes and practice in them. We tend to go for more structural strength because we don’t have a lot of time for paddling up north, when every lake freezes over during the school year. Instead, we focus on stability […] talk to other schools about their mixes, and take our paddlers’ opinions and suggestions from being on the water.”
To test the concrete, the team creates multiple batches of the mixture, which are cured for differing lengths of time (from seven to 28 days) to see which interval creates the strongest concrete. One crucial test comes when the newly cured sample concrete is thrown in water. “It has to float,” said Chittick. “Our concrete is less dense than water, which will allow it to rest on top of the waves. So it’s pretty safe to assume that the canoe will float, before you even consider buoyancy.”
The team uses purpose-built, homemade tools and a hot wire to cut large blocks of Styrofoam into the individual pieces – nearly 30 of them – which, when glued together and tensioned, become the mold or shell of the canoe. Then, three separate batches of concrete are spread into the mold, each a mere 1/8” thick. A layer of fiberglass mesh rests between each layer, adding strength. In a rules twist introduced this year, concrete canoes may not be colored with paint, only dye, which alters the composition of the outer layer. Finally, the canoe is placed in a humidity chamber. “We want the concrete to be as wet as possible without submerging it,” says Chittick. “That will allow the concrete to have higher strength.” The canoe is kept in the chamber for 14 days, then removed and allowed to cure an additional 14 days before the mold is finally broken.
The final product of this intensive effort is a 242-pound, 17.7-foot long canoe that handles like no commercially available canoe on the market. “It takes a lot of force to get a 242-pound object moving,” said Chittick. “It’s at least four times as heavy as a regular canoe. And once the rowers start into a turn, the weight takes them around a corner. Our team had trouble getting it moving. We’ve tried different modifications over the last year, and each time it hasn’t worked that well for us,” he said. “We’re still trying to figure out the whole design.”
Cypher kept a close eye on canoe performance at nationals. “The biggest [problem] is turning,” he said. “You can see if the paddlers make a slight movement and the canoe keeps turning, which means that the canoe has too much momentum. You can see the paddlers switching sides too much trying to keep the canoe straight. You can see if a canoe is rocking too much for the paddlers and keeping them off-balance. That’s not usually our problem. Some schools really focus on just racing, and you can see when they turn they look like they’re going overboard.”
And what about the sturdy, stable UW-Platteville canoe? “There were 25 teams at nationals, and overall, we got 12th,” reports Chittick. “We placed 18th in our design paper, 13th in our oral presentation, and overall in the races we were part of an eight-way tie for last.” Cheeringly, however, the UW-Platteville team placed 8th overall in final product. Chittick knows what changes he’d like to make next year: “We have a lot of stability in our canoe, and next we’re going to hopefully thin it out so we can improve our straight line racing.”
As the team plans next year’s sleeker, faster version, the intangible gifts of Concrete Canoe become apparent. Cypher feels the competition has emphasized the crucial importance of teamwork. “It teaches you that you have other people to rely on and bounce ideas off of. When you’re unsure, you ask – there’s always someone around to help.”
“It’s taught me a lot,” agrees Chittick. “It’s a leadership opportunity and a problem solving opportunity all in one. Every year when the rules come out for the competition, we read them over and learn all the new changes, like the switch from stain to dye, which changed the way we had to design the canoe. It threw us for a loop, but I don’t think there was a single person on the team who wasn’t willing to take the leap and go the extra mile to make those changes. We had one person bring in a testing method which they had picked up in class months before, and we implemented it. We need the whole team to make things happen. We have to trust other people to step up and make decisions and help reach our goals.”
Written by Jane Halpern, College of EMS writer
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