Last weekend, travelers at a rest stop in Minnesota became alarmed when a group of college kids pulled up in a U-haul truck, carefully unloaded a large, sleek object from the back, and set to work on it with power tools. About the length of a person, it was painted white and resembled a torpedo. Fearing the worst, someone called the police.
“They thought it was a bomb,” said Alan Orthmann, a junior studying mechanical engineering at the University of Washington. As a cop car pulled up to the rest stop with sirens blaring, Orthmann and his classmates had the unusual task of explaining to the police that the object wasn’t a weapon at all. It was a human-powered submarine, on its way from Seattle to the 10th International Submarine Races outside of Bethesda, Maryland, and it wasn’t quite finished.
For the last two weeks between finals and the cross-country trip to the competition, the team had done nothing, said rising junior Kees Beemster Leverenz, besides eat, sleep, and work on the fiberglass vessel.
“We’ve been going on about 4 hours of sleep,” he said. “This week we’ve been bringing [the sub] out of the base every night to work on it.”
When I caught up with the team on the last day of the race, held for the 7th time at the Carderock Naval Surface Warfare Center, they were the sort of cheerful that comes from being very, very tired. Their submarine, the Beluga, was propped on a carpenter’s horse, and the team was waiting for the glue to dry on some buoyancy foam before they could give the vessel another shot in the water.
“We’ve all spent way too much time together,” Orthmann added. What keeps the team from going nuts in each other’s company? A steady supply of energy drinks, burritos, and laughter. “If we’re in a bad mood, we know it’s time to eat,” he said.
The scene around them was like a very bizarre tail-gate. Trailers, trucks, tents and subs from twenty-three universities (and one high school) from across the US and as far away as Mexico, Canada, the UK, and Venezuela crowded a parking lot. Volunteers barbecued hot dogs while competitors traded power tools, advice, and friendly banter; several teams were performing last-minute repairs on their home-made subs. Meanwhile, in the eerie greenish water and half-light of the Tow Pool, wetsuit-clad students readied their vessels for the timed race.
When you see how small and sleek the submarines are, it seems incredible that anyone can fit inside. The pilot, clad also in a wet suit and equipped with scuba gear, places his or her oxygen tank in the fiberglass belly of the submarine, then lies prone on top of it. With his or her head in the submarine’s pointed nose, feet clipped into bicycle pedals that drive the vessel’s propeller, and hands gripping the rudder control and the release bar of an emergency buoy, pilot and sub sink several feet below the surface and the hull fills with water.
“Stay with the boat at all times, and don’t panic,” advises Nate Leibolt, a 16-year-old high school student who occasionally pedals the Scuba Doo, a creation by a local team of high school students, college kids, and Carderock civilian employees. “It’s not hard to pilot, and really fun.”
Usually used by researchers to test scale models of Navy ships, the 20-foot-deep Tow Pool had been rigged into a submarine race track. A “speed trap” wired to a poolside mission control captured the subs’ top speeds just as they’re nearing the 100-meter finish line, and Navy divers waited at the end to wrangle the vessels to a stop. The joke is that pilots who can evade the Navy divers win a special award (none did). Competitors in dry clothes or wet suits still dripping from a recent dunk perched along the pool’s edge, while teachers, parents, and volunteers rushed about.
“It’s 1 pm and I’ve eaten part of my sandwich, so that’s a really good day,” joked Kurt Yankaskas, a Navy ship designer and five-time submarine racing judge. He told me his son and daughter were in the pool, operating the underwater cameras; the competition shows live video of the racing subs on large screens. “The most rewarding part is seeing the kids progress and be successful,” he said. “Their siblings here, and we’ve lit the spark in some of them, too.”
One of the most successful teams was Florida Atlantic University, who held a narrow lead with a top speed of 6.298 knots, or a little more than 7 miles an hour. Charlotte George, an ocean engineering student who had helped create the fins on the Talon 1, told me about the physics of the subs. The torque from the propeller causes a cylindrical hull to roll slightly, but fins and a slightly non-cylindrical body keep it from tilting too much. Additionally, George said, “We want as little drag as possible. We have a vinyl sticker on our hull, and if it’s bunched up even a tiny bit we cut it so it’s flat. It’s like a swimmer shaving their legs to get that little bit of speed.” A purely horizontal sub also helps; an upward or downward tilt increases the surface area cutting through the water. This all depends on getting the buoyancy just right.
“The more neutral [the sub is] the easier it is to control it,” George said. By counteracting the pilot’s buoyant wet suit with weights, and the weight of the submarine with buoyancy foam, the team achieved a ship that stayed wherever they placed it in the water. But Bath University was having a harder time; air exhaled by their pilot was getting trapped in top of the hull, causing Sulis, named after the Celtic god of the sea, to float to the surface nose-first. So far the team had been unable to complete the 100-meter-long course, so they borrowed a drill from the
University of Washington team to make air holes.
“This is all very experimental,” said Gavin Bishop, a rising senior majoring in mechanical engineering at Bath. But the seat-of-the-pants fix, the culmination of more than a thousand man-hours of design and construction, won them last-minute success; on their final run they were able to clear the course.
“It’s been stressful, because we’ve taken time out of our studies to do this,” said Alessandro Dos Santos of the University Simon Bolivar team, who had journeyed all the way from Venezuela to compete. Their sub, which hadn’t passed the initial safety tests all week, cleared the course in the last few hours of the competition. They weren’t going to win, but they had succeeded. “I like to get my hands dirty,” he said. “I don’t care if I don’t sleep or eat, I’m having fun and doing what I like.”
Update: Congratulations to students from Florida’s Springstead High School for snagging the first prize in overall performance for their sub, Sublime. For full results of the races, visit the official International Submarine Races website.