Innovative Technique to Enable Floating of Concrete Canoe in Water

Credit: Texas Tech University

MacGyver will feel proud. Although escaping before anything explodes does not seem to be a life-threatening condition, it is really a hard task to perform something that, on the surface, is impossible, namely, making concrete to float.

However, this is the aim for engineering students across the state, attending the annual American Society of Civil Engineers (ASCE) regional conference each year. Concrete canoe races are a part of the conference, which includes seminars and an opportunity for students to get in touch with industry pioneers who will become their employers one day. As part of the canoe races, the students design, construct, and race canoes made of concrete.

The concrete canoe competition, at least at the national level, has been around since 1985 because we held the first national competition here,” stated Audra Morse, a professor in the Department of Civil, Environmental and Construction Engineering at Texas Tech University. “We haven’t always been very successful with our canoes in the past, but for the last eight to 10 years we’ve had a solid set of canoes that have left Texas Tech and floated off and done well.”

The regional conference and competition for this year was conducted in March in El Paso, where the Texas Tech team was in the fourth place. The team comprised freshmen and sophomores who did not even attend the basic construction materials classes before being involved in the project in the fall. The team won the second place last year.

I felt we had a good boat. I don’t know that it was better than last year but it was up to par with it. Our presentation was good, but I felt we needed to do more. Answering questions, we struggled with that because most of us are underclassmen and we haven’t taken the classes we needed to answer the harder questions. We had a few deductions from our display which messed us up, and then our races weren’t as good as last year.

Elizabeth Hall, Sophomore Co-Captain, Texas Tech University

Constructing a floating, working concrete canoe on the surface is very difficult. However, the rules are modified each year, compelling the teams to change their plans and remodel the canoes. Consequently, it might not be possible to construct a stable structure with the ability to float.

However, the competition not only enables the team members to be a step ahead in furthering their academic careers but also renders them to be more appealing to employers after their tenure at Texas Tech.

We meet with professionals at the conference, and those are some of the people that, down the road, you’re going to be working with,” stated sophomore Thomas Wiseman, the other co-captain of the Texas Tech team. “All the judges there come from schools that have competed in this and have been co-captains before, and they all know each other and work together.”

Following the rules

The concrete canoe competition is a months-long competition wherein students have to construct their canoes that conform to specifications put out every August by the ASCE. The change in rules every year includes the materials allowed to use in the concrete mix to different dimensions of the boat.

Concrete mixes used earlier have included materials such as Styrofoam beads, perlite, and glass spheres (i.e. materials lighter than rocks) as its aggregate material. For the year 2016, similar to other teams, the Texas Tech team used glass beads and air bubbles in the concrete mix rather than sand to reduce the weight of the material lighter. However, for 2017, the ASCE restricted the use of glass beads and air bubbles to only 25 percent of the total mixture.

Hence the Texas Tech had to look for a different aggregate material to be mixed in the mixture. Consequently, the team zeroed in on pumice, which a porous, light-weight volcanic rock.

Adding the pumice didn’t change the mix that much. It added some weight to it. Last year it was at 194 pounds and this year it was a little over 215. We took a bit of length and a bit of height off of it, so that made up for the higher weight.

Elizabeth Hall, Sophomore Co-Captain, Texas Tech University

Upon deciding on the formulation, the team had to test not only its potential to fit on the boat’s mold but also its strength and buoyancy. This is because the teams have to literally race the canoes during the competition.

During the fall and part of the spring, the student spent time analyzing their mixes to zero in on the best mix, and came up with the final mix not less than 28 days before to the drop-dead pour date as the concrete had to cure over the mold. The Texas Tech team selected a “male mold” in which the concrete is poured around and not inside the mold. The male mold comprised flexible plywood strips covered using sheetrock and freezer paper.

We spent probably 50 hours in the shop in one week just to deal with our pour that weekend,” explained Wiseman.

In the mean time, students also prepared a report on the canoe to be presented one month before the competition. The team is also making a cutaway of the canoe to demonstrate the way in which it was built.

The teams should also demonstrate any theme or flair using the boat. The Texas Tech team selected a theme based on the “Pirates of the Caribbean” movie. Their demonstration paid tribute to the scene in which the pirate tries to steal a ship by taking a canoe underwater. In the Texas Tech team’s demonstration, the canoe was upside down with legs protruding out from below.

Then, the students gave a 5-minute presentation related to their canoe, the innovative or new features on which they worked that year, and the recyclable material used, if any.

However, just carrying the canoe to the competition can be difficult as it is loaded at the back of a trailer and secured tight enough. The trip can lead to formation of cracks in the canoe, and students are restricted to the materials they can use to fix the canoe.

There are certain rules, and you’re not allowed to use an epoxy and things like that,” stated Russell Carter, an instructor in civil engineering and one of the faculty advisers for team. “Tape is used a lot, and that is something that is looked for in the Texas section. It’s called the spirit of competition. We look for schools that help one another when something like that comes up.”

However, the teams have to undergo one more test before the competition, namely, the swamp test.

For investigating the resiliency and buoyancy of the canoe and its constituent materials, water is filled into it and deliberately sunk. Subsequently, the team waits for it to resurface. This notifies the judges that the canoe is safe and ready for the competition. According to Morse, the teams often tape foam to outer side of the boat to assist it to resurface.

That counts against them later on, but it’s still part of the spirit of the competition,” stated Morse.

Working together

When the time for the competition approaches, even boarding the canoes can be difficult, stated Morse. The teams normally lower the competitors into the canoes instead of letting them climb into it as it may lead to formation of hole in the sidewalls. However, this is all part of the teamwork to be learnt by students for successful completion of the project.

You are working with a bunch of different people, and that’s good,” stated Wiseman. “It’s an important part of the project because that’s what we will be doing every day for the rest of our lives, working with a team. We had our ups and downs and didn’t agree with everyone. But the teamwork was the most important part of the project.”

Although the Texas Tech team could not finish well compared to the previous year, they were very happy about the outcomes of their months-long hard work.

We wanted to make our display really stand out, which we did, and it was good. There were a lot of good parts. The best was the compass that displayed our cross-section, and we put a lot of work into that one. The ribs for the boat were delayed about a month and that pushed us back a bit, and then we had to build the mold within a week to meet our pouring day. That was our biggest challenge, but it was worth it.

Elizabeth Hall, Sophomore Co-Captain, Texas Tech University

According to the co-captains, the fun part of the competition was moving around and having a look at other canoes and the manner in which other teams worked on the challenges. This enables the students to acquire better ideas for the next year race.

Our new co-captains are in charge now but we’ve already started talking to them about some new designs,” stated Hall. “We’ve got a few ideas that we may want to try out.”

Wiseman as well as Hall stated that they obtained a wide knowledge by attending the race, which helped them not only after graduation but also in the class at present as they are applying the knowledge acquired in the competition to class work.

It was a really hard year, but I’m glad we did it,” stated Hall.

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