Three Holbrook Junior-Senior High School students have been named the ninth-grade Massachusetts winners in an engineering competition sponsored by the Army. Elizabeth Brady, Sarah Walsh, and Rachael Hobart worked after school with seventh-grade science teacher Jason Welch to adapt a student-made robot from a different competition last year so that it would be capable of moving onto the sea floor of Boston Harbor, locate abandoned lobster traps, and retrieve them. Welch said the idea was to help the environment by removing a potential hazard to navigation and wildlife. In the students’ testing, the robot did not find any lobster traps, but he said they plan to try again. Each student received a $1,000 savings bond from the Army-sponsored eCYBERMISSION program, which challenges students in grades 6 through 9 in science, technology, engineering, and mathematics.