MARBLEHEAD – A low turnout of voters replaced a sitting selectman Monday in a stunning upset.Elected to the board for the next year were incumbents James Nye, Judy Jacobi and Jackie Belf-Becker, along with former Selectman Harry Christensen and political newcomer Bret Murray.Selectman Mike Rockett, seeking his second one-year term on the board, finished sixth, followed by Cemetery Commission member RoseAnn Wheeler McCarthy.Rockett finished ahead of Murray in Precincts 3, 4, 5 and 6, but not by enough to move ahead. He shook hands with Murray and left Abbot Hall after the Precinct 2 results were posted.?I?m speechless,” Murray said. “I?m a political outsider running for the first time and I beat an incumbent. I?m a little awe-struck.”Murray thanked his supporters and the voters and said campaigning outside the polls Monday was “a pleasant surprise.”?People told me they were impressed with my performance at candidates? night,” he said.Murray is an Eagle Scout with 13 years experience in insurance risk-management. He is a permanent intermittent police officer in Marblehead. His father, Thomas Murray, served as Marblehead?s director of public works and his brother is a captain in the town fire department.The incumbents congratulated Murray and Christensen, but Selectman Jackie Belf-Becker said Rockett will be “sorely missed” and Selectman Judy Jacobi called her victory “bittersweet.”?We lost a really good selectman tonight in Mike Rockett,” Jacobi said. “I?m not too happy about that.”Observers estimated voter turnout at 10-15 percent. Final figures were unavailable last night.In a close race, incumbent Dick Nohelty and challenger Thomas Connolly were elected to the School Committee. While Connolly led in six of the town?s seven precincts – all but Precinct 6 – less than 90 votes separated them. Professional appraiser Barton Hyte finished third.Connolly said the most gratifying part of his run was being at the polls Monday.?It was a well-fought, well-run campaign,” he said. “I?m on Cloud 9. I can?t believe it.”In the day?s third contested race, incumbent Charles O. Phillips survived a challenge from alternative energy firm CEO John Arata for a seat on the Municipal Light Commission.