ENGINEERING: THE NEXT GENERATIONS

A high school wins against major universities in human-powered submarine races.
by Peter Easton, Copy Chief

No kidding. There really are submarine races.

And when the winners were announced for the 9th International Submarine Races last summer, there was an upset.

In the field of competing engineering universities from the United States, Canada, Mexico, and the United Kingdom there was a high school—Sussex County Technical High School of Sparta, N.J.—sharing top honors.

Victorious Sussex County Technical High School team members show off the result of their efforts. They had support from many sponsors.

Sussex took home first prize for innovation among the 26 human-powered submarines in the competition, and third place in best overall performance. It was one of only two high schools to compete in the event.

The races are held every second year in the David Taylor Model Basin at the Naval Surface Warfare Center's Carderock Division in Bethesda, Md. The competition is organized by the Foundation for Underwater Research and Education, based in Brunswick, Maine. Major sponsors are the IEEE Oceanic Engineering Society and the Electric Boat Corp.

According to the ISR Web site, each team must develop a one- or two-person "wet" submarine. Two-person subs must have one person providing the propulsion and the other navigating and steering. Both crew members breathe from an air supply carried aboard.

Solving Practical Problems

A race is contested in a 22-foot-deep tank, and the course length is 100 meters. The sub must be entirely submerged for the length of the race. As the event manual points out, "Bear in mind that by definition, a submarine travels completely submerged, so a run down a course where the submarine never quite submerges cannot be declared official."

The sub races bring students together to solve practical engineering issues, giving them a taste of what the professionals do for a living. Participation also introduces them to sophisticated engineering concepts.

"This isn't a theoretical educational exercise," said Chris Land, an instructor and project manager who works with the Sussex team. "We have 10 months to design and manufacture the entire submarine. You can't jump into manufacturing until you are comfortable with design. And, you don't want to spend students' time and energy on something that doesn't work."

It doesn't hurt the team's chances that Land once served as an engineering officer on a nuclear-powered submarine.

Sussex competed in the races in 2003 and 2005. During the 2005-06 school year, Terry O'Connor, who pedaled the school's entry, UmptySquatch II, in 2005, made it his senior project to redesign the sub's propeller system for more speed. At the same time, Land was studying fluid flow as part of his master's program in mechanical engineering at Stevens Institute of Technology in Hoboken, N.J.

The best hull design turned out to be 16 feet long, about six feet longer than any previous design. The longer hull proved to have the best thrust-to-drag ratio.

Land enlisted the aid of Blue Ridge Numerics, which develops CFD software called CFdesign. One version of the software was designed to work with the CAD system that the Sussex team uses, Solid Edge from Siemens PLM Software.

The study of the vessel's fluid dynamics included the hull. The team settled on an ellipsoidal hydrofoil wrapped around a common axis. They didn't know it at the time, but the shape was similar to that of the International Submarine Races world record holder.

The CFD results brought some surprise. After testing, the best hull design turned out to be 16 feet long, about six feet longer than any previous design.

"I asked the students to take about four feet off the end and test a shorter profile," Land said. "But the longer hull proved to have the best thrust-to-drag ratio. Once we found that out, the hull didn't look so big."

After Terry O'Connor graduated and moved on to West Point, Adam Schatteman, a senior in charge of the technical design group, took over the task of refining the propeller design. (Schatteman is currently majoring in biomedical engineering at Rutgers University.) Unlike a motor-driven sub propelled at a high, constant speed, a human-powered sub is subject to greater flow fluctuations. The human pedal-power that drives the sub tends to create an irregular flow, making propeller efficiency especially important. Sussex's previous designs contained flat portions that would cause drag as water flowed over the surface.

With the changes to the hull and propeller designs, the team's final best speed was 1.694 knots, representing a slight improvement over the previous best time.

The pilot used arms and legs to earn first place in innovation as a result of "first design and successful operational demonstration of a human-powered propulsion system utilizing both upper and lower body muscle groups," according to the citation awarded to Sussex. It was also cited for having the first operational sonar system in ISR annals.

Land, an ASME member who majored in chemistry as an undergraduate at the University of Richmond, believes that the 10 months of experience with upfront CFD, coupled with another year of ISR experience, will enable Sussex to continually improve in the years ahead. For the students, exposure to a project like this in high school will give them an advantage at the university level, he said.