Some construction paper, tape, toothpicks, scissors, and a Styrofoam plate (I save the ones that come with the produce I buy--they come in handy in all sorts of projects--painting, making small boats to sail to the new world, etc.)
They made it! We did three heats in a double elimination round. All the boats were great with lots of ingenuity put into them. But in the end, it was Dev's super slime/ huge sails/smooth bottom boat that cut straight through the water and made the fastest average time. Yeah, Dev!