Santa Clara mechanical engineering student John Zevenbergen pulled his hands out of his sweatshirt pockets and adjusted his red skull cap, patting the hat's emblem, worn off a little on the side.

"It's my Steve Zissou patch - for good luck, so we get out there," Zevenbergen grinned. "Yep, we'll get out there."

Zissou, a fictitious Jacques Cousteau played by Bill Murray in off-beat auteur Wes Anderson's "The Life Aquatic with Steve Zissou," might be proud of the scene he surveyed around Zevenbergen at the Boatworks Marina in Tahoe City Thursday morning: A half-dozen students working on a future-primitive-looking underwater robot whose shiny squared yellow chassis looked more New York cab than sleek diving machine.

Beside the yellow waterbug (The Triton) was its candy apple red younger sibling (The Nautilus) similarly boxy, yet spherical, resembling a fire hydrant souped up with 8-inch propellers.

Zip ties and cables and loose wire and brand-new laptops and dive equipment and sunflower seeds and empty Redbull cans decorated the rest of the staging area. Zevenbergen, restless, clasped shut his laptop and stowed it on top of his diving gear, turned and broke into a half-hearted jog toward the dock where the UC Davis' research vessel, the John Le Conte, fired a plume of exhaust as it bobbed in the choppy morning whitecaps coming off Lake Tahoe.

"We're gung ho," said Zevenbergen's professor Chris Kitts, the founder of the six-year-old underwater rover program, and mentor to the young engineers who journey to Lake Tahoe annually in late-May to make dives with and troubleshoot their mechanical creations.

"He does more projects than any professor," said Gio Minelli, a first-year mechanical engineering grad student and third-year veteran of the underwater rover team. "I can't answer for all these guys, but I didn't think about robots much before I joined the program. Then, you get in Chris' lab and it's amazing. It's computer engineering and mechanical engineering - plus you get to play with toys all day, what's better than that?"

Upon receiving the go-ahead from Kitts to ready the crew, Zevenbergen patted his lucky cap once more and ran back to the parking lot staging area to load up the robots and ready his diving gear.

"Yep, we're going."

As the Santa Clara gang loaded their gear, four geologists representing University of Nevada, Reno and the U.S. Geological Survey stood on the dock and reviewed underwater maps of Lake Tahoe and talked about Monday and Tuesday's dives.

A recent theory that Tahoe may have had an "ancestral lake" predating its existence (about 2 million years ago) was being further proven with this trip, creating a buzz for the geologists.

The ancestor lake was shallow and hot and made of loose rock sediment, the geologists speculated. The lake bed was not made of the sheer granite rock which is familar on the mountains rising above Lake Tahoe.

Instead, the lake bed was comprised of the loose rock beneath the surface on the West Shore, Tahoe City and Sand Harbor, which, in case of a seismic event, could easily dissolve, dramatically altering those shorelines.

"I don't want to send waves of panic through Tahoe, but an earthquake of a 7 magnitude can hit, and when it does it has the power to move the lake surface near the fault line three to four meters," said Dr. Rich Schweickert a professor of geology at UNR. "That translates to a possible tsunami wave of about 10 meters.

"But catastrophic events like this happen once every 10,000 to 20,000 years. It's not like the chance of a wildfire - but it's something people should be aware of."

During this week's three-day series of voyages, Schweickert, Mary Lahren, a fellow geology professor at UNR, Winnie Kortemeier, a PhD candidate from UNR and Jim Moore of the USGS, were transfixed with the notion that rolling boulder lines discovered near Tahoe City and on the West Shore gave credence to the ancestral lake theory.

The annual trip is also key for individual research, Kortemeier said.

"My study is in young volcanic rock, and this trip really helps me get a closer look and get a feel for what's down there," she said. "It's great working with the Santa Clara guys. I know they're mainly interested in how their equipment is working, but I don't think they have any idea how much this collaboration helps our research."

The worlds of geology and engineering came together two hours into Wednesday's research trip just off Sugar Pine Point State Park on the West Shore. It was on the shallow shelf that the Triton's new mechanical arm, controlled abroad the boat with a joystick and remote 80 meters above, grasped at a granite rock.

"That's a good sample right there, grab it - grab it," Kortemeier said to Paul Mahacek - a first-year grad student from Santa Clara.

Mahacek, with the nerves-of-steel gaze, grabbed the rock remotely and placed it into the Triton's basket, with the care of a child pulling at a teddy bear's ear with an arcade claw.

Cheers and high-fives permeated the cramped swaying cabin of the Le Conte as Mahacek spun the underwater craft in a quick circle, dusting up lakebottom sand in an impromptu celebration.

"That's what I'm talking about," he said.

Hours later, tired from the midday sun, water supplies running low, but spirits lifted, the geologists sat digesting the day's events along with some salami and cheese from the rooftop deck of the Le Conte. As the lake's choppiness subsided to a breezy lap, they gazed appreciatively down at the Santa Clara crew pulling the rovers from the water.

"It just gets better every year," Schweickert said. "We can start looking for joint grants for programs like this. It's exciting the amount of research we are getting done, but the possibilities seem endless."

Indeed, Santa Clara's Kitts, who uses grant funding to keep the program afloat, said his students are currently working on a shallow-water rover that would overtake the Triton as the biggest in the fleet - and could explore the lake's bottom.

"All in due time," he said.

As if on cue, Santa Clara student Zevenbergen surfaced from his dive, spit out his mouthpiece, removed his mask, looked down toward his flippered feet churning beneath the clear surface and said to nobody in particular:

"Amazing."