Dave Hossenlop (front) and Tim Smallidge use cardboard oars to paddle their way to the finish line in the Spencerport High School pool.

Spencerport high school teacher Dave Walsh gave his students what he hoped would be a watertight assignment - and for most, it was. The 16 students in Walsh's Principles of Engineering class had to make and then race cardboard boats as part of the structures unit.

The students had to follow elaborate rules with the human-powered, corrugated cardboard boats. Boats had to complete two lengths of the pool carrying 400 pounds, which included at least two people. The paddles were also made of corrugated cardboard. No more than 10 percent of the boat's surface could be covered with tape. Before constructing the boats, students had to complete design drawings and models. Only one boat sank by the time the racing was completed on January 19 at the Spencerport pool.