Image courtesy of Redgate/Kane

A Boston-based developer’s proposal to redevelop a vacant Portsmouth federal building into offices and high-end residences could be in for rough waters.

Following the city’s Nov. 5 municipal elections, the one city councilor who opposed the 154,000-square-foot plan from The Kane Co. and Redgate Capital Partners for the McIntyre Federal Building won the mayor’s seat. Worse for the development team, voters turfed out five of the six incumbent councilors who supported the plan and sought reelection.

Developer Michael Simchik, a cofounder of the Revisit McIntyre group, said the result was caused by “the lack of transparency being shown by the incumbent council and their devotion to the wishes of the city manager,” according to the Portsmouth Herald.

The City Council had voted 8-1 in August to move forward with the Redgate/Kane proposal, acquire the 2.1-acre site from the federal government and enter into a development agreement. The council rejected a petition organized by Revisit McIntyre to reconsider the vote by the same margin.

Redgate plans to renovate the existing, landmarked McIntyre building for office space and build two new buildings containing 76 apartments and 92 covered parking spaces on the site’s current parking lot. Simchik has proposed a more limited redevelopment that would create a park in place of the two new buildings, although the Revisit group has not specifically endorsed the project.

The federal General Services Administration still must review the project before it can proceed.