Monday, March 17, 2003
Copyright © Las Vegas Review-Journal

Row, Row, Row Your Boat ...

Engineering students put skills to test to make concrete float

Photos by Clint Karlsen. Vance Skidmore shows off a piece of concrete left over from his team's efforts to build a concrete canoe. This canoe, built almost entirely from concrete, was entered in a contest two years ago. The team didn't win, but the canoe still serves a purpose: It's an ice chest for social gatherings. Rich Zaragoza, an engineering student at UNLV, is helping to build a 24-foot-long steel bridge that he hopes can withstand 2,500 pounds of weight.

When someone with access to a bucket and a garden hose mixes water with cement, adds sand, a sandlike ceramic powder and a few special ingredients, the resulting gray paste will harden into concrete when it dries.

If the mixer has done the job correctly, the way a budding engineer with a goal in mind would do it, the concrete will be half as strong as regular concrete and will be lighter than water.

It will float.

And so, it would be possible to build a concrete boat. A 20-foot-long canoe for four, perhaps.

"To me," said Vance Skidmore, a UNLV engineering student who has spent the past six months immersed in the intricacies of concrete canoe construction, "it's normal."

Skidmore, 25, is leading a cohort of engineering students in a quest to build a fully functioning canoe from a special concrete they've concocted.

The students -- from the University of Nevada, Las Vegas' student chapter of the American Society of Civil Engineers -- will travel to Arizona on the first weekend in April to match their canoe up against those from other southwestern universities.

The winner of that competition, and from 19 others around the country in the coming weeks, will travel to Pennsylvania in June for the national finals.

Each year, the engineering group sponsors a nationwide search for the best concrete canoe builders. It's been going on for 15 years.

UNLV's students never have placed higher than third in regional competitions. But this year, the students say, things should be different.

"It'd be great to go to the nationals," said Skidmore, a junior who has worked on the canoe in past years. "That's my goal."

Last year's canoe had problems, he said. It cracked because, apparently, the students didn't use the right ceramic powder, or maybe because it dried too quickly. The canoe built two years ago fared better, and the students still use it today as a makeshift ice chest for social gatherings.

In all, 47 students are expected to attend this year's regional competition at Arizona State University, said Pam Willenberg, 30, a senior engineering student.

And, she said, canoeing isn't the only thing on the agenda.

"I'm pulling my hair out right now," said Willenberg, who is acting as the chapter's chairwoman for the event.

Some students are building a 24-foot-long steel bridge that must withstand 2,500 pounds of weight without breaking.

"We tested a couple of sections, and it held up well," said Rich Zaragoza, 34, a senior engineering student who has led the team's bridge building effort. Their bridge broke last year when a weld failed, he said.

"This year, the welds won't fail," he said.

Also on the agenda is a concrete bowling contest, Willenberg said.

But it's the concrete canoe competition that has the students most buoyed.

Preparation for this year's event began early in the fall semester, Skidmore said. The students had to figure out just how to mix the concrete. This year, he said, they're using a finer ceramic mix. The mix, which looks and feels like fine beach sand, is comprised of tiny, and hollow, ceramic balls, he said. They're what makes the concrete so light.

They also had to concern themselves with the strength of the canoe. Sometimes at the competitions, canoes will break apart in the water.

"It's actually pretty funny," Skidmore said. "They have to send powerboats out there to rescue the team."

Seriously, he said, the competition teaches students real applications for the concepts they learn in class. Plus, it gets them attention from members of the local engineering community.

"People who work on the bridge and the canoe, they often get good jobs when they graduate," he said.

Of course, it helps if the team does well in the competition. And so, in an effort to keep its canoe from cracking apart, Skidmore said the team this time around has reinforced the concrete with steel cables and a piece of rebar.

They also radically redesigned the mold. In the past, they've just poured the paste over a hunk of Styrofoam shaped like the inside of a canoe. This year, they fashioned an elaborate, two sided mold that's used to smoosh the concrete into the shape of a canoe. The design should provide for a more consistent thickness, Skidmore said.

The team just poured the concrete into the mold a week ago, and they plan to remove it Saturday. It needs that long to dry, he said.

Designing a concrete canoe that floats wasn't the team's only concern. The slender boat also will have to move quickly through the water as four team members row it through a slalom course.

The performance in the course will count for 30 percent of their score.

"We're all very excited," Skidmore said.

And so, not wanting to leave anything to chance, the team has been out at Lake Mead as often as possible in recent weeks, practicing their rowing technique.