Principle
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.
Read more about this topic: Concrete Canoe
Famous quotes containing the word principle:
“A state of war or anarchy, in which law has little force, is so far valuable, that it puts every man on trial. The man of principle is known as such, and even in the fury of faction is respected.”
—Ralph Waldo Emerson (1803–1882)
“Whether our feet are compressed in iron shoes, our faces hidden with veils and masks; whether yoked with cows to draw the plow through its furrows, or classed with idiots, lunatics and criminals in the laws and constitutions of the State, the principle is the same; for the humiliations of the spirit are as real as the visible badges of servitude.”
—Elizabeth Cady Stanton (1815–1902)
“To light one candle to God and another to the Devil is the principle of wisdom.”
—José Bergamín (1895–1983)