School stories / St. Paul’s School, the week before winter break, December 2022
The Cardboard Boat Race Was Won by Dropping the Oars
Schools test Archimedes' principle by putting students in cardboard boats. At St. Paul's in 2022, a coxswain who had never had to row took the helm, and the oars failed her.
On December 15, 2022, the last day before winter break at St. Paul's School in New Hampshire, students in Ben MacBride's Physics II class gathered barefoot at the school pool. In groups of four, they had built cardboard boats that had to float while carrying each group's captain, and survive a race down the 25-meter pool. The unit was Archimedes' principle. Everyone had passed the swim test. Lifeguards stood by.
Four boats went in. Two quickly took on water, and the race became a two-boat event.
One captain was a senior who coxed for the girls' crew team, the small person at the back of the shell who steers and shouts and does not row. Her team's boat was named from a combination of all four members' names, and she later called it a hydrodynamic masterpiece. She had a smooth entry, she told the school. Then the oars failed her. Her teammates told her to drop the oars.
She did. She started paddling with her hands. The other boat had been two lengths ahead. In the last quarter of the pool she was neck and neck. "What brought me to victory? My teammates' boisterous cheers ushering me on," she said. "I probably would've drowned the boat without them."
Three years of steering eight rowers, and the first time she has to move the boat herself, she does it with her hands.
Afterward, members of all four teams jumped in to retrieve the sinking boats and help their captains out. MacBride called it a fun send-off.
Other schools do it outdoors. At Choate, the Physics Phlotilla has crossed the campus pond since May 1995; in 2026 the fastest boat, Paddle Bus, made it in a minute and fifteen seconds. At Darlington School in Georgia, students get two four-by-eight sheets of cardboard and 60 yards of duct tape to cross Silver Lake. In May 2026, twelve of twenty-five teams made it.
Twelve of twenty-five. The other thirteen were also learning about Archimedes, just more quickly.
The middle one built a cardboard boat in our bathtub last winter to float his action figures. It held three and sank with four. He said this proved something. I asked what. He said it proved that the fourth one was too heavy, which is Archimedes' principle in its purest form.
Sources
The public records, school pages and published accounts this story draws on. Where the story imagines a scene or a line of dialogue, that is the column’s telling, not a quotation.
- Choate: Physics Phlotilla Floats On in Spectacular Fashion choate.edu
- St. Paul’s: Physics Students Sink, Swim and Set Sail sps.edu
- Darlington / Rome News-Tribune: Cardboard boats, real lessons darlingtonschool.org