ASEE Prism Magazine - September 2003
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On Campus

An underwater finish line

- By Robert Gardner 

Over five sweltering days in June, teams of submariners donned wet suits and raced their craft through the cold waters of the Navy's David Taylor Model Basin in Bethesda, Md. As part of the 7th International Submarine Races for human-powered submarines, 19 teams of engineering students from universities in the United States, Canada, and Mexico—along with students from a few high schools—tried to overtake team "Omer 5" from Ecole de Technologie Superieure in Montreal, holders of the current world speed record.

The biennial competition gives engineering students the opportunity to apply their knowledge of hydrodynamic design, buoyancy, propulsion, and underwater life support. They work for months, sometimes years, on their craft. Though many team members are mechanical engineering majors, students from multiple disciplines were involved. "We worked with people from the art school, mechanical engineering, electrical, and aerospace," says Eli Rosenburg, co-captain of the University of Michigan's "Mercury" team.

From their staging area in the adjoining parking lot, teams wheeled their one- or two-person subs to the loading platform. Resembling an extremely long rectangular swimming pool, the 3,200-foot-long basin yawned before them. After the inevitable last minute changes, the subs were lowered into the chilly water and the pilots prepared to enter their craft. Submarine size varied, with some not much larger than their single crewmember to others measuring 16 feet to contain their two-person crews. The brightly colored hulls, adorned with names of school and corporate sponsors, were hand built and made of fiberglass.

Once the pilots were inside, the hatch was closed and the submarine flooded to send them toward the bottom. To get moving, the pilots pedaled a bicycle crank, connected to a driveshaft, to turn a propeller. But not every sub had a propeller. Virginia Tech's "Specter 1" used a dolphin-like fin attached to the pilot's legs to move. "We can't wait to see what this baby can do," said race director Jerry Rovner. That baby took first place in the one-person, nonpropeller division with a speed of 4.05 mph.

A submarine's speed over the 328-foot course is clocked at the starting line, a 32.8-foot-wide speed trap in the middle, and the finish line. A team of Navy divers in an inflatable boat tracked the submarines from above and divers occasionally jumped out to check on a troubled sub. Not content to merely oversee the races, the divers decided to try piloting Sussex County Technical School's "Umptysquatch-1." It wasn't as easy as the students' made it look after months of practice; none of the Navy divers were able to complete the course.

The impromptu nature of the divers' attempt aside, completing the race course wasn't easy. Technical glitches abounded: propellers broke, shear pins snapped, hatches broke off, and guidance fins failed. Even when everything held together, navigation mishaps in the dimly lit waters of the tank were common. "They all experienced the same problems," said chief judge Claude Brancart. "It is gratifying [however] to see these teams react, respond, repair and get back into the competition." And to receive help from their competitors. Despite the serious competition, interteam cooperation flourished. When the University of California at San Diego's "Invicid" veered sharply during a run and smashed its nosecone against the wall, other teams helped with the repairs. Within hours it was racing again.

In the end, no one was able to end the Canadian team's dominance. "Omer 5" registered a new world record of 7.84 mph. But there were surprises. Springstead High School's "Sublime II" managed to edge out its collegiate competition by getting into the water first on opening day. A technical glitch forced its crew to surface but, unlike the Navy divers, they eventually finished the course.

Robert Gardner is an associate editor at Prism.
He can be reached at rgardner@asee.org.

 

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