Posted on Mar 18, 2005

Eric Jacobs '05 and Chris Lewis '05 launch their boat

The final competition of the mechanical engineering senior design seminar featured tricked-out bathtub toys from a century ago: putt-putt boats.


In an event on Tuesday that looked rather like a swim meet, students circled a kiddie pool, cheering loudly for each other, and against their professors. As one heat finished, Prof. Ann Anderson announced the next wave of contestants, who eagerly prepared their boats at the starting line.


The “Putt-Putt” Boat, a favorite toy of the late 19th- and early 20th-century, uses a primitive steam engine powered by a candle flame. The boat is propelled as steam flashes out the tail pipes, condensed steam pulls fresh water back into the boiler, and the cycle starts again, giving the boats their characteristic sound.

Closeup of a Putt-Putt boat

Anderson was introduced to the boats when her mother got some for her children. She appreciated the engineering and decided to use them in a course.


Today, the boats are mass produced from recycled soda cans in countries where labor is cheap. They cost about $7 in the U.S. through various web sites.


But the engineers were tasked with a major redesign that used only the power source of the matchbox-size toys. They had to design and build a new hull from ABS plastic using the College's prototyping machine, a 3-D printer. They were judged on speed, cost, payload and operating temperature.

Marc Donovan '05 celebrates victory over a faculty boat

“At least the professors aren't competitive,” said one student, sarcastically, as Prof. Brad Bruno lowered the faculty entry into the water.


Bruno and Prof. Phil Kosky had reengineered a dream boat complete with dual candles, a thrust vector to control direction and pitch, camphor on the hull to break the surface tension of the water and a large aluminum shield to block the heat detector that would determine their operating temperature. The two professors noted that their consulting fees for such a project on the outside would have run in the thousands of dollars.


Their boat went straight and fast.


But in a run-off, another boat hit theirs and sent it off course, allowing a third boat to cruise across the finish line.


The students erupted in cheers, one commenting, “Who needs a Ph.D. to run a boat?”