Concrete Canoe

By Kara Potter

 

I am currently a senior at Cornell University and a co-captain of our school’s concrete canoe team. This year we are looking to build our canoe mold from cut sections of foam.

As promised I have attached some pictures of our team working with the scroll table you sent us. We have run into some snags in testing our small models which have set us back somewhat on the schedule so we have not started on the large mold as of yet.

We make a concrete canoe every year for an annual competition. The Concrete Canoe Competition has been going on since the 1970’s with the first national competition being held in 1988. The competition is hosted by the ASCE (American Society of Civil Engineers). Each year the rules are released in September, and the rules are slightly different each year so that a team cannot just reuse a previous year’s boat. This year the focus is on environmentally friendly construction and the rules mandate that two of the aggregates used in the concrete need to be recycled materials. We are members of the Upstate NY Region. Our regional competition is in April and the regional winner will compete at the national competition in California this July. Last year our canoe weighed 400 pounds. In order to compete in the competition each team must successfully complete a “flotation test” which consists of filling the canoe up with water and making sure it still floats. If the boat does not pass this test the canoe cannot compete. However the team is allowed to add flotation to the boat to make sure it passes the test. Last year’s canoe for us had foam in both ends to make sure it passed the test. At competition there are 5 races, 2 for women, 2 for men, and 1 co-ed race. There is also an oral presentation and paper that must be presented about the canoe. Points from the races, oral presentation, technical paper, and final appearance of the canoe determines the regional winner.

  Glad to hear you liked the pictures. The foam cutter has been great for us and has worked really well. This year we were challenged to build the canoe to a 1/16″ tolerance and because of the precision that your foam cutter offered we were able to do that. The pictures that I sent you are of us constructing our male mold. We basically make the male canoe shape from floral foam, cover it in liquid latex (which is the covering that you are seeing in the picture) and then we build a box around it. Once we have the box we fill it with expanding foam and let that harden. Finally we flip the box over so the expanding foam is on the bottom and the floral foam is on the top. We then remove the floral foam and peel up the latex (that is one of the only things that we have found that doesn’t actually stick to the expanding foam) and we are then left with a hollowed out canoe shape. I will send you more pictures of that boat when we have them. We just cast the boat today so it should be a few weeks.