Printing a boat

From the article:

University of Washington mechanical engineering students braved uncharted
waters as they paddled to the finish line at the annual Milk Carton Derby
at Green Lake in Seattle in what they believe is the world's first boat
made using a 3-D printer.
The new UW student club Washington Open Object Fabricators (or WOOF)
built the boat as its inaugural project. The club's blog describes
the undergraduate members' 10-week quest to make equipment and develop
techniques to be first to print a seaworthy craft.
Judges weren't sure how to qualify the UW entry, which used recycled
milk cartons for its buoyancy but not quite in the way that contest
organizers had envisioned. In the end, the boat raced as an unofficial
entry in the adult open category, where it placed second.