However, the calendar, which would go into effect next fall, is drawing strong opposition from the city teachers union, which says it violates provisions in its contract concerning changes in work conditions.
The Coordination Committee voted Tuesday to approve a 175-day calendar, versus the current schedule of 180 days.
The change was prompted partly by the realization the district can meet the state mandates for minimum instruction based on days or hours. The required 990 hours for high school and middle school instruction would be compressed into 175 days, with the school year ending about a week earlier than it would under the 180-day calendar.
The proposed calendar would also make Dec. 23 a no-school day. For the 2013-2014 year, the last day of school would be June 12 for students and June 13 for staff.
Under the proposal, the additional class time would be incorporated into the school day by cutting the lunch period in the high schools, currently about 50 minutes, in half.
Mayor Ted Gatsas, a strong proponent of the change, said this would bring the lunch times in the high schools in line with those at the elementary and middle schools.
"Parents say their kids don't have enough education time," he said. "This would give them more of that."
However, Ben Dick, president of the Manchester Education Association, said the move violated a condition of the contract concerning changes in work conditions, since it would add to the work load of teachers.
"To accommodate the extra work hour, this would take away part of the lunch period and add to the work period," he said.
Dick said a memorandum of understanding with the district already prohibited any changes in the start and stop times for work - the beginning and end of the school day.
He also noted that the union had made it clear to the subcommittee that it considered any unilateral changes to the school day a violation of its contract.
"We've come to the conclusion that we need to handle this within the bargaining process," Dick said. "We've been preparing our members for this topic of discussion for some time."
The teachers contract expires at the end of this school year, but if no agreement is reached on the new contract, the current one will remain in force. Negotiations on the new contract are just getting under way.
Only two members of the Coordination Committee voted against the change to the calendar, Art Beaudry and Debra Gagnon Langton. The policy is expected to be voted on at the full board meeting next month.
The Coordination Committee voted Tuesday to send another potentially controversial policy to the full board: establishing a maximum and minimum enrollment for high school classes.
The policy would set a maximum class size of 30 students and a minimum of 15, below which the class would be cancelled.
The committee approved an exception to the minimum clause, in response to concerns raised by some school board members, as well as officials in Hooksett, which sends its high school students to the city and is locked in a dispute with the district over school conditions.
The revised policy states that "specific course extensions may be granted by the superintendent or his/her designee."
Board member John Avard had objected to the minimum enrollment component of the policy over concerns that it could lead to the cancellation of advanced and specialized courses, such as music, that tend to have fewer students.
"I think there needs to be more flexibility for special circumstances. I believe principals know when there is a special case, for example if there are only nine students in an Advanced Placement history class," he said.
Avard had proposed the amendment to the policy, and he ended up voting for the revised version.
The only vote against the policy came from board member Beaudry.
The policy proposal was prompted in large part by the outcry from Hooksett parents and education officials over crowded classes in the Manchester high schools. Hooksett has begun the formal process of ending its contract with the city over the conditions.
In a letter to the city school board sent prior to Tuesday's meeting, Hooksett Superintendent Charles Littlefield said the 30-student limit "is consistent with school approval requirements."
The town school board, however, had concerns about a 15-student minimum.
"It is the board's sense that many of these classes meet the unique needs of individual students and could have a negative impact on the overall breadth and depth of their high school experience," Littlefield wrote.