The bright blue pool is ringed with clusters of teenagers and adults who’ve come here representing high school and college robotics clubs from Hawaii to Newfoundland. In the water, tethered to elaborate homemade control stations, underwater robots dive, spin and dart through the water like brook trout. Divers follow their progress with underwater cameras. Jimmy Buffet is blaring from speakers. The weather on this June weekend is relentlessly sunny. The mood is part physics lab, part pool party.
Welcome to this year’s (Remotely Operated Vehicles, for those in the know) to determine which of these nearly three dozen teams will outmaneuver (and out-design) the rest of the pack. The contest involves exploring a "mystery reef" and performing seven tasks within 25 minutes. Your mission includes finding and recovering a lost "sonar" device, a mineral sample and specific species of fish; patching a leaking barrel, and tagging a mussel bed and a "methane leak" of bubbling air. Oh, and while you're down there, you have to enter a sunken “U-boat” and read an inscription on the ships bell.
Just to make things more interesting (and realistic) you have to control your sub using just two TV monitors that feed back pictures from onboard cameras, just as you would if you were miles offshore exploring in thousands of meters of water.
The annual event, sponsored by the Monterey, Calif.-based Marine Advanced Technology Education Center, brings together a group of ocean engineering professionals to judge the designs and watch the subs run through their paces in a pool at the University of California at Santa Barbara, a sprawling campus on the Pacific Ocean with a gorgeous view of the Santa Ynez Mountains.
MIT is here, of course, but so are dozens of other colleges and universities, high schools and community colleges -- even a group of home schoolers from Langley, British Columbia. The designs they’re working on are just as diverse: everything from compact, PVC pipe frame models to cubic-yard, metal-framed monsters filled with wires, cameras, motors, propellers and gripper arms driven by dashboards outfitted with joysticks, switch panels and laptops.
I’m here with my son and the team from Milton Academy in Massachusetts, which is busy with numerous last-minute fixes and modifications needed to thwart the assorted gremlins that attack these homemade devices.
Tackling the reef
With school out for the summer, about half of Milton’s core team is here: Will Joo, Dan Lee, Sam Minkoff, Matt Schoen, Kristen Tsai, Alice Tin, and SeoHyung Kim. All were involved in the design and construction of the sub, nicknamed “Herbie.”
The team’s faculty advisor, Tom Gagnon, is a science teacher who became interested in remote-controlled submersibles three years ago and at first had students design robots that could play an underwater version of Quidditch, the broom-flying sport played by Harry Potter and his classmates. (For more on the rules of Quidditch, consult the nearest 10-year-old.)
Team members take on different tasks on race day. The “tetherman,” for example, is in charge of handling the 40-foot umbilical cord packed with cables that connects the sub in the pool to the TV monitors and control devices housed in control shacks set up on the pool deck. The “drivers” (nominated by the team based on their video game acumen) will control Herbie's horizontal and vertical motors and its "grippers": the devices that let the sub pick up objects.
The team has just gotten its first look at the “reefs,” the underwater PVC frames wrapped in black plastic tarps with holes where the remote-controlled subs enter. But this set-up is different than the one the team navigated in the New England regionals, where Milton took first place.
“We’re screwed,” one team member observes. “The U-boat is much too dark.”
This sets off a spirited discussion about whether to add a flashlight to augment the LEDs mounted to the front of the sub:
“The extra mass will make it less maneuverable.”
“How about holding the flashlight with the gripper and then dropping it?”
“They (the judges) won’t like that.”
“What about more LEDs? Or moving them to the front?”
“Too much work.”
“Are you allowed to drop glow sticks in the reef?”
“No, they wouldn’t let us do that.”
“They never said you couldn’t.”
The contest is divided into two classes: Explorer (unlimited voltage, more or less anything goes design-wise) and Ranger (limited to 25 amps: blow a fuse three times and you’re out.)
Some of these subs have more corporate logos than a NASCAR entry. We’re in the Ranger class; our team is more on the PVC-and-twist-tie-construction, funded-by-pizza sales end of the scale.
After unpacking and inspecting the gear, the team realizes it’s missing a monitor. Someone is dispatched to find the local Costco for a $99 monitor and to stock up on epoxy glue, 16-gauge wire and duct tape and to locate the nearest Radio Shack for emergencies.
Then the vertical motors start acting up: This will make navigation difficult and restrict the amount of weight the sub can lift.
“They’re making this noise. Like ‘Brrrrzzzzhh.”
“Did you check the wiring?”
“What’s the amperage of the motors?”
“It depends on the load.”
It turns out the sub's "waterproofing" (duct tape and liberally applied hot glue) has sprung a leak: When removed and checked, inky water spills from each motor. Spare motors are tested in a dorm bathroom sink, but they appear to have less power than the waterlogged pair. Is it the motors or the wiring? The spares are attached anyway.
Determined by random drawing, our team’s mission is scheduled for Saturday at 4:15 pm. The schedule also includes a half-hour design review with a NASA engineer and a Silicon Valley computer chip designer at the unwelcome hour of 8:45 am.
The review involves a detailed discussion of weight and buoyancy, thrust calculations and amperage draws. The team speaks fluent geekspeak as they field questions from the two professional engineers. Is their ROV positively or negatively buoyant? (Translation: left alone, will the sub float or sink?) It turns out that Herbie is “slightly negatively buoyant.”
Back at the pool, a major malfunction crops up. The replacement of the vertical motors somehow changed the wiring. The grippers and motors work, but not together, so the motor wires need to be switched. Worse, one of the wires in the tether has apparently broken. There’s no way to rip it apart and repair it in time. But the team decides that by rewiring the remaining leads, they can make it work. Out comes the soldering iron again. With minutes to spare, Team Milton moves to the control shack for their mission.
Disaster strikes almost immediately: the front camera dies. After successfully tagging a mock “methane leak” of air bubbles, the team decides to haul Herbie out of the water and reposition the lone working camera (facing bottom) to the front. Out come the twist-ties. Like an Indy 500 crew changing tires, the operation takes about 30 seconds, and the sub is back in the water.
But after successfully completing five of the seven tasks, Herbie is scraping along the bottom: the vertical motors, probably waterlogged again, are too weak to generate lift. The team tries changing batteries. Still weak, the device slowly rises and after several attempts, a Velcro patch is partially attached to the mock leaking oil drum.It’s a decent showing, but the competition here is tough.The team from Cambridge Rindge & Latin School wins the category. Milton comes in No. 10 out of 23, but goes home with a design award for Herbie's grippers.
Still, the students are clearly disappointed. The post-mortem centers on the front camera. What made it fail? One team member grabs a meter to go check the power source: Was it somehow putting out too much power? At 12.7 volts, that possibility is ruled out.
With the mission over, we head for dinner on the beach. As the twilight slowly turns to darkness, a few team members wade into the surf. There, someone finds an abandoned bicycle covered with seaweed, missing a front tire. But the chain looks okay, and the brakes work. Maybe with a new wheel, and a little WD-40 …