Skip To Main Content

Unthinkable Ship

update: Congratulations to the ONU Concrete Canoe team for finishing second overall at the North central student conference April 7-9! The team placed first in the oral presentation category and third in the design category. Due to the extreme cold, the canoe races were canceled.


ONU engineers turn logic on its ear with a concrete canoe.

In the film Titanic, there is a scene where the ship’s designer Thomas Andrews, confronts the grim reality of the claims that his ship is unsinkable. “She’s made of iron, sir! I assure you, she can [sink]... and she will. It is a mathematical certainty,” he says. It begs the question of why we build things that float from materials that don’t?

At Ohio Northern University, the answer to that question is simple: Because we can. In fact, ONU has an entire team of students who work all year devising new ways of doing just that. And on Saturday, April 9, the ONU Concrete Canoe team will get to show off its skill at doing the unthinkable against other colleges and universities at the 2016 American Society of Civil Engineers (ASCE) North Central Student Conference when they race a canoe made entirely out of concrete.

Launch the concrete canoe photo gallery

Follow the ONU Concrete canoe team on Facebook for race results

You read that correctly. A canoe. Made of concrete. It might sound like an absurd premise, but it’s actually not impossible. In fact, engineers have figured out how to make a rather decent boat out of pretty much the last thing you would ever want to cling to stay afloat.

The secret is that concrete is a very versatile material. It’s created with a formula, or recipe, of ingredients. Depending on those ingredients, it can be made strong or made weak. It can flex, or it can be brittle. It can be heavy, or it can be relatively lightweight. Use the proper recipe and apply some basic boatbuilding principles, and concrete can float.

Anyone who has ever bought a bag of concrete from a home improvement store knows what it looks like. There is a fine powdery component (cement) and a bunch of small rocks (aggregate.) When mixed with water, the cement undergoes a chemical reaction that causes it to harden around the aggregate, which makes the resulting material strong. Since commonly available concrete is used for mostly for construction applications, strength is more important than weight, but it doesn’t have to be heavy. By replacing the rocks with a lightweight aggregate like foam pellets or polyester fibers, and by reducing water weight, concrete can be light enough and yet still strong enough to build a canoe that will float.

ASCE concrete canoe competitions are really excellent teaching tools because they push engineers to apply the sum of their engineering prowess toward gaining a competitive edge. The focus isn’t on just building a canoe out of concrete, it’s about trying to build the best canoe out of concrete. Every single aspect of the building process is analyzed and refined, from the hull design, to the concrete formula, to the canoe construction itself.

Building a canoe like this does not happen quickly, and it cannot be done alone. The ONU team is 27 students strong, with each one contributing considerable time to the project from the very start of the school year. As project manager, senior Emily Puleo, a civil engineering major from Greensburg, Pa., had to first build a team that could tackle each aspect of the endeavor before she could ever build a boat. Leadership roles exist on the team for experienced students in the form of team officers. There is a hull design officer, a mix design officer, a construction officer and an aesthetics officer. The team also has a paddling coach and a fundraising and recruitment chairperson.

Voting is usually pretty unanimous,” says Puleo. “We don’t think to nominate someone new when someone has experience doing the job. I always try to get someone underneath every officer so they know what they are doing and can take over the next year.

With the officers in place, the team begins to build their canoe. The first step is hull design. A 170-pound canoe requires a lot of energy to paddle, and the last thing the team needs is to fight to keep it going in a straight line. That’s why hull design officer Victoria Smith, a senior civil engineering major from Dunkirk, Ohio, incorporated a keel, or shallow “v” shape, to the bottom of the boat to help them paddle true. The hull is designed on a computer, and the file is sent to a company that builds a mold from Styrofoam, which the team has traditionally built its canoe around. However, the team will build the canoe inside the mold this year, as for the first time ever, the team is having a female mold made. Puleo hopes that it will save the team from sanding the canoe, which is a necessary yet time-consuming step to help reduce drag on the canoe as it moves through the water.

With the hull designed and sent to the mold maker, a group of team members search for the perfect balance of the best ingredients for the concrete mix. In all, ONU’s team tested a dozen different mixes before settling on one to use in the construction of their canoe. The third step is the mixing and bagging process. This allows the team to make small batches of the concrete on “pour day” so that they can work with them in an efficient manner and ensure consistent curing. Pour day is a bit of a misnomer, as there’s no actual pouring of wet concrete like you might for a sidewalk. Instead, part of the team mixes small batches of concrete and shapes them into flat sheets of uniform thickness that another group of students applies to the mold’s inner surface like tiles, blending the edges together as they go. After the entire canoe is covered, a layer of plastic mesh reinforcement is placed on top of the concrete. The team will complete this process a total of three times in a very long day.

Then it’s a month before anyone touches the canoe again, as the concrete needs all of that time to cure properly. This is the perfect time for the team to work on its paddling, and so that’s what they do every Sunday night right in the ONU natatorium in a big red fiberglass canoe.

“The pool’s not that big, so we are really good at turning. It’s going straight that is more difficult,” says Puleo.

On Saturday, the ONU Concrete Canoe travels to the campus of Michigan State University, the site of the very first ASCE national intercollegiate concrete canoe competition in 1988, to compete with their canoe in and out of the water. The North Central Student Conference is more than just a rock regatta. Teams will be judged and graded on more than sheer speed. Each team must write and present a technical paper that explains how they made the canoe and must be prepared to answer questions about the choices they made throughout the process. There also is an aesthetics competition that highlights the best themes from the competing teams. ONU channeled their inner Game of Thrones and went with a medieval theme for their canoe.

Here’s to hoping that the winner is coming from Ada, Ohio, this year.