A concrete canoe is a canoe made of concrete, typically created for an engineering competition. In spirit, the event is similar to that of a cardboard boat race—make the seemingly unfloatable float. However, since concrete and other poured surfaces are an integral part of a civil engineer's education, concrete canoes typically feature more development than cardboard boats. Principles Ignoring hydrodynamic effects, all ships or boats float because the weight of the water they displace is equal to the weight of the boat (Archimedes' principle). However, many boats are made of materials that are denser than water, meaning that the boat will sink if filled with water. Although it is not required by the rules of the competition, some competitive concrete canoes have concrete mix designs that are less dense than water. They must pass a test in which the canoe is filled with water and pushed below the surface; the canoe must then resurface in order to qualify for racing. This is possible because, unlike normal concrete which uses sand and small rocks, concrete canoes are created with porous aggregates such as Macrolite and microspheres. However, because many teams still design their concrete mixes to be denser than water, in the United States, teams are allowed to insert concrete-covered, non-structural foam pieces in their canoes to make the canoes float after being submerged. ASCE National Competition The ASCE (American Society of Civil Engineers) National Concrete Canoe Competition (NCCC) provides students with a practical application of the engineering principles they learn in the classroom, along with important team and project management skills they will need in their careers. The event challenges the students' knowledge, creativity and stamina, while showcasing the versatility and durability of concrete as a building material. Each year, the NCCC, which is held in mid-June, is hosted by an ASCE Student Organization. Some 200 university teams attempt to qualify for the NCCC by placing first in one of the 18 conference competitions held throughout the United States during the spring. Until 2018, teams placing second in a conference competition behind a university that finished in the top five at the previous year's national competition are also invited. This was replaced by the Wild Card drawing in 2018. If the Concrete Canoe team was part of a student chapter that placed within the top one-third of all annual reports, and the team finished within the top half of all