In the final weeks of his tenure on the Vashon Island School Board, John “Oz” Osborne has put forward a new approach to address what has become one of the board’s toughest issues.

Rather than ask Island voters to approve funds for an ambitious school construction project in one bond measure, he suggested Thursday night that the board consider a phased approach, giving voters two separate opportunities to weigh in on the district’s building needs.

This February, under his plan, the school district would ask voters to approve a $30 million bond for a new 40,000-square-foot classroom structure at the high school and a full renovation of its aging gym. The second phase, to go before voters in February 2012, would seek $21 million to renovate Building A, the high school’s crowded main structure, as well as improve the district’s technology infrastructure and mechanical systems.

“My real motivation for this was solving our immediate needs around the classroom building,” he told the other board members. “By building the classroom building first, we knock off that very important need.”

The plan comes at a critical time for the five-member board.

Since the district’s request for a $75.5 million bond failed last March, the board has been weighing several options, including a scaled-down version that would go before voters in February, seeking $55 million for a new classroom building, a fully renovated gym and several other projects.

If it decides to go for a February vote, the board will need to make a decision in the next few weeks.

At Thursday’s meeting, board chair Bob Hennessey noted there was a danger in phasing a project that the board wants to see completed in its entirety; voters, he noted, might approve one phase and not the other.

“But we tried a non-phased approach, and the voters didn’t buy it,” he told his colleagues.

Dan Chasan, another board member, said he felt a phased approach “might be a little disingenuous” if it were simply an attempt to lower the price tag in February and to make the project, at first blush, more politically palatable.

Other board members noted that the real issue is the board’s lack of consensus on a renovation to the high school’s gym, which, at nearly $10 million, has weighed in as one of the pricier items under consideration.

“Let’s be honest,” said board member Laura Wishik. “Some members of the board feel the gym has to be done now, and some don’t. … We’ve got to resolve that.”

Osborne, who did not run for re-election and thus will be leaving the board in a few weeks, said his motivation was to try to find a new way to think about the project as he and other board members home in on the final outlines of another bond measure.

“This is not a fait accompli,” he said in an interview. “It’s just another way of parsing out the capital needs in a time of economic uncertainty.

“My preference and maybe the majority of the board’s preference, is still to do something like the $50 to 55 million plan,” he added. “However, if the board finds there are other political realities, this other plan may be the way to go.”

The Vashon Island school board will hold a special working session at 6:30 p.m. Thursday to try to reach consensus on a bond measure for a district-wide construction project. The meeting will be held at the McMurray library.