A Rock-Solid Idea that Floats: Engineering Students Build a Concrete Canoe

Demonstration of the M-305 Canoe was part of National Engineers Week

Coral Gables (February 25, 2013) — A life vest strapped around her torso, Catie Goldstein stood midship beside the 22-foot-long green and orange canoe that rested on the bank of Lake Osceola as her classmate Matt Kowalski grabbed hold of the craft’s stern.

With a mighty shove, the two University of Miami engineering students launched the canoe into the still waters of the lake, jumping into the hull and promptly picking up oars as it began to float away.

They paddled to one end of the lake and back, slicing effortlessly through the current. By its appearance alone, the sturdy watercraft wouldn’t normally turn heads. But pound a fist against its frame, and you’ll discover that it’s as solid as rock. That’s because the boat is made entirely of concrete—cast in a wooden mold by Goldstein, Kowalski, and a team of College of Engineering students who used ingenuity and clever design skills to make sure it could glide through the water while carrying the weight of two rowers.

The students showed off their hefty but speedy boat on February 20 as part of National Engineers Week. Showcasing the important contributions engineers make to the world, E-Week on the University of Miami campus included a duct tape stickup competition, a Build It contest for local high school students, an innovation expo, and Introduce a Girl to Engineering Day.

The Row Across the Lake event last Wednesday was more than an exhibition of a concrete canoe’s seaworthiness. It also displayed the cleverness employed by engineering students in designing such a craft and making sure it could sail. Before the canoe was cast, students designed it on a computer.

“Our canoe is pretty similar to a canoe made of conventional material,” said Goldstein, a senior majoring in civil engineering who is also president of the UM chapter of the American Society of Civil Engineers (ASCE). “Like conventional canoes, our boat’s performance depends on weight, hull shape, and basic maneuverability. Since reinforced concrete is not a common material for constructing canoes, the biggest challenge we faced was balancing the strength and workability of the concrete mixture.”

To achieve that critical balance, they used aggregate and concrete, mixing the ingredients in a wooden male mold that resulted in a 200-pound canoe with a quarter-inch-thick hull, port, and starboard. They named the craft M-305, giving it an orange and green paint scheme and military-style lettering. Cenospheres—alumina silicate hollow ceramic particles mixed into the concrete—added volume while decreasing weight.

The M-305 has already been used in competition. In 2011 UM engineering students transported it to Tennessee Tech for a contest among concrete canoes, entering it in sprint races and maneuverability drills.

It is the forerunner of the Black Pearl, a 20-foot-long concrete canoe born from a female mold to give it a better hydrodynamic shape. UM civil and mechanical engineering students will use that boat to compete in one of the events at the ASCE Southeast Student Conference, which will be co-hosted by UM and Florida International, March 14-16.

A third concrete canoe, The Heat, won sixth place for overall appearance in a competition at Florida State. Mariah Szpunar, a senior mechanical engineering student from Chicago, helped design that canoe, giving it a Miami theme. She also served as the craft’s co-captain. “But rowing hasn’t always been one of our strong points,” said Szpunar, who has already accepted a job as a systems engineer in missile and fire control at Lockheed Martin.

For civil engineering student Kowalski, working on the M-305 gave him a chance to apply classroom principles.

“We learn everything in class, but it’s all on the board,” he said. “It’s not until you work with the materials that you find out how theories actually work in real life.”

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