By Brian Messenger
---- — It’s a 132-pound canoe made of concrete. But it floats — so well, in fact, that 20 area college students, including an Andover resident, will race their physics-defying vessel in a national competition this week.
“I thought concrete was heavy,” said David Nader of Andover, recalling his first impression of ULowell’s concrete canoe. “It was the knee-jerk reaction that I get from everyone. I had the same reaction.”
That was three years ago. Nader is now a two-time “mix captain” charged with designing and testing the concrete mixture used to make the canoe ULowell is sending to the national Concrete Canoe Competition.
This year’s competition, sponsored by the American Society of Civil Engineers, runs this Thursday through Saturday in Illinois and includes 22 other collegiate teams from across North America.
Other ULowell team members from the area include Zachary Greene of Haverhill, Brendan and Michael Sprague of Methuen and Aikaterini Dimitriou of Pelham, N.H.
The trick, of course, is making the concrete canoe lighter than water.
To do so, Nader and his teammates used microscopic glass beads as an aggregate base and mixed it with cement. The resulting concrete mixture floats because the beads are light enough to counteract the weight of the cement.
“That’s the key to making it float,” Nader said. “It took a lot of trial and error.”
To land a spot in the competition, the students in April placed first in a regional qualifying round.
In addition to race results, teams will be judged on their canoe design, construction quality and presentation quality.
ULowell finished 13th in the national competition last year. But Nader, who expects to complete his master’s degree in civil engineering in December, said he and his teammates are heading to Illinois with high expectations.
“We have a much better product,” Nader said of their current canoe. “I’m looking at a top-five finish this year.”