
May 15, 1998

UW floats its boat with concrete

By LUCY BODILLY
Special to the Journal

The Dawgs beat those Cougs and this victory was a real upset. It was at the regional Concrete Canoe races, sponsored by the Master Builders and American Society of Civil Engineers.

The University of Washington beat Washington State University for the first time in several years.

UW concrete canoe

The University of Washington's "Centennial" recently won the regional Concrete Canoe races.

"It was fitting that our boat Centennial won this year because it is the 100th anniversary year of the UW School of Engineering," said Eric O'Brien, UW team co-leader.

In all, four schools competed in the regionals, according to Bruce Chattin, executive director of the Washington Aggregates and Concrete Association, who was a judge at the competition. Gonzaga University, Spokane and St. Martins College in Lacey also sent teams.

In addition to the actual race, the winner is determined by canoe design, technical papers and presentations.

"It was a hoot," Chattin said. "The canoes ran the gamut from Corvettes to ones that looked like concrete canoes."

Boats of all kinds have been constructed from concrete since 1847, including many vessels during World War II when other construction materials were difficult to obtain. With large ships, concrete poses less of a maneuverability problem. With canoes, it can make turning unwieldy. The engineering challenge comes from designing a canoe that is light enough to be easily mobile.

"Basically, a pound of the concrete mix you design has to weigh less than a pound of water in order for the canoe to float," O'Brien said. Contest rules forbid hollow spaces in the hull, but flotation devices can be used at the bow and the stern, if they do not add to the structural integrity of the canoe.

In fact, mobility was one of the reasons UW edged out WSU this year, O'Brien said. Hoping to enhance maneuverability, the WSU team went for an extremely light mix design which resulted in an 80-pound canoe. Unfortunately, it would not bear the weight of the paddlers, and their knees went through the bottom. UW's canoe is considered in the mid-range at 130 pounds.

The University of Washington won by putting its canoe Centennial up against Wazoo's Gneiss. Gonzaga's canoe, Rock Bottom, weighed about 215 pounds. St. Martins College did not submit a written report, but did enter the race.

O'Brien credits this year's victory to better project management than in the past. According to the competition rules, canoe construction could not start until the academic year in September. But potential racers started perfecting their paddling skills, working out with weights and watching their diets last July.

"There are some nationally-ranked canoeists here and they have been helping out with the athletic side of the competition," O'Brien said. In the past, the students focused on finishing the canoe and technical paper, and left the paddling techniques to the last minute.

The UW design focused on creating a fairly light-weight canoe that would remain maneuverable in the water. Student engineers used standard cement, but added perlite, a gardening material made of hollow rocks, for its aggregate instead of the traditional gravel. UW testing labs were at the team's full disposal. At the end, the concrete design mix achieved 1,200 psi, significantly lighter than normal concrete. In comparison, the design mix for Gonzaga's Rock Bottom reached 5,200 psi.

Previous experience taught the UW team it would be easier to use the outside of a concrete form to shape the canoe. A cross-section shows concrete shaped around steel wire mesh. The design team placed drywall, which was removed before competition, on the outside of the canoe to ensure a smooth exterior finish. Raw materials for the canoe cost about $3,000. But add in the cost of labor and the use of outside consultants and the cost skyrocketed, O'Brien said.

The UW team is still hoping to raise $12,000 to go to the National Competition in Rapid City, S.D. So far, local concrete companies, the Washington Aggregates and Concrete Association and Pozzalanic Northwest have supported the cause. To make donations, call O'Brien at (206) 663-8898.

O'Brien and his team are confident that they stand a chance at nationals. "Lots of the powerhouse teams got bumped this year," O'Brien said. "We have a good chance to show the rest of them up. The last time UW won at nationals was in 1982."