A small, bright yellow submarine dubbed Seahorse III stopped on cue and submerged on command this week in a pool at Southern Methodist University.

The university's Robotics Club hopes its $30,000 machine will make those decisions by itself later this month when it tackles an underwater obstacle course as part of the Autonomous Underwater Vehicle Competition in San Diego.

"By the time we get there, we'll know that it works correctly," said Nathan Huntoon, a team member and electrical engineering graduate student. "If it isn't, we'll be working all week to fix it."

That's exactly how the SMU team spent the competition last year after thieves swiped the submarine out of the backseat of a student's car just days before the competition. The team worked feverishly to rebuild the submarine after police recovered it.

Their work paid off as they placed 11th out of 28 teams. Now, three veteran members and three newcomers hope to build on that success.

After competing last year, the team quickly began working to raise about $30,000, including more than $5,000 in parts, to re-engineer and upgrade the submarine.

The new model uses a complex system of cameras, underwater microphones and computer programs to navigate on its own in depths up to 50 feet, Mr. Huntoon said.

The competition, which begins July 29, challenges teams with a series of obstacles that range in difficulty, and points are awarded for completing each obstacle. The winner of the competition receives $8,000.

"We want to win, but realistically, we would like to be in the top three," Mr. Huntoon said. "That's doable."

The team members said their experience gives them an advantage because they know how to correct potential problems that might arise during competition.

"That's what makes us a better candidate for winning," said Michael Buynak, a team member who is also a graduate student in electrical engineering. "We know how to correct those problems."

The team also learned the most important lesson – keeping the submarine locked up.

"We will keep it under armed guard," Mr. Huntoon said jokingly.