After negotiating a severance package for County Executive Bern Ewert, who resigned yesterday after three stormy years as Prince William's top manager, supervisors turned inside county government for an acting successor, appointing Craig S. Gerhart to the job.

Gerhart, 44, is a 17-year veteran of county government in Prince William, having arrived in 1983 as assistant to the county executive. He has held numerous jobs, serving as budget director for several years and most recently working as one of Ewert's two deputies.

Gerhart was not available for comment yesterday afternoon.

Regarded as smart, Gerhart is also outgoing and popular with the Board of County Supervisors and county staff. In many ways, he is the insider that Ewert never was and could never be.

Ewert, whose relationship with supervisors was rocky almost from the start, was hired on a close 5 to 3 vote in 1997. Despite his aggressive and popular agenda to control the sprawl that has overtaken Prince William over three decades, Ewert found himself at odds with a board antagonized by his sometimes brash management style.

Yesterday, after he emerged from his final closed-door meeting with supervisors to announce his resignation, six board members praised Ewert for bringing a new vision and new ideas to the county, among them are the slow-growth plan approved 17 months ago and a recognition of the potential of developing the county's Potomac River waterfront.

Ewert successfully championed measures large and small--a "tax-trigger" scheme to start reducing the county's sky-high property tax when revenues reach a certain point, bonds to build state-of-the-art soccer fields and renovating existing ones, and first-ever strategies to address blight in some of the county's older neighborhoods. There was even a litter squad of employees assigned full time to pick up trash, because Ewert said the county's image mattered.

"You are a true visionary and a man of very high energy," Supervisor Hilda M. Barg (D-Woodbridge) told Ewert yesterday.

Supervisor Mary K. Mill (R-Coles), a critic of Ewert's, nonetheless complimented his efforts. "The county is a much more beautiful place than it was when you came here," she said.

Ewert also is credited with hiring Prince William's first economic development chief, Martin J. Briley, who in a relatively short time has lured several high-tech businesses, including America Online Inc., to the county.

But ultimately, Prince William's top manager and its elected officials proved to be a rocky match. Ewert alienated supervisors on more than one occasion by charging ahead with projects without consulting them--leaving them scrambling to share the credit.

"It's been a very interesting experience," Ewert, 57, said yesterday, moments before his resignation. He noted that when he arrived in March 1997, he said he intended to stay for three to five years. "This is three years, what I expected it to be."

Ewert does not have another job. He said he plans to pursue consulting--and possibly another job in the public sector--from his home in Charlottesville. He has a rented apartment in Lake Ridge.

It's not known whether Gerhart, who lives with his family in Lake Ridge, will bring new ideas to the job or step back and allow supervisors to take the lead.

Although supervisors said yesterday that they intend to conduct a search for a permanent county executive, several said they are likely to look inside the McCoart Administration Building to fill the job. Another strong contender is Deputy County Executive Pierce Homer, the board's well-respected lobbyist in Richmond.

In other business yesterday, supervisors agreed to amend their rules governing public speaking period at board meetings. In recent months, the public input period has been the occasion for angry outbursts from residents.

When speakers address the board on matters of personnel or litigation, Chairman Sean Connaughton (R) will inform them that supervisors cannot respond directly. And speakers, now limited to a maximum of three minutes during both afternoon meetings and evening public hearings, will be restricted to just one topic at each meeting.

CAPTION: "It's been a very interesting experience," County Executive Bern Ewert said moments before resigning.