By Geoff Davidian

SHEBOYGAN, Wis (Reuters) - The first-term mayor of Sheboygan, Wisconsin, a self-described alcoholic, faces off Tuesday against seven opponents including a high school student in the city's first mayoral recall election.

Mayor Bob Ryan's recall election comes the same day opponents of another Wisconsin politician -- Republican Governor Scott Walker -- plan to file petitions to force him into a special election only a year after he took office.

More than 4,000 Sheboygan voters signed petitions to force the election for Ryan, who was caught on tape making sordid jokes about a sister-in-law and was photographed passed out in a tavern during a drinking binge last summer.

Ryan, 48, a married father of three, admits he was a binge drinker and considers himself an alcoholic but said he has not had a drink for months.

"I did a lot of really foolish, stupid things," Ryan said Monday in an interview at his City Hall office.

He said the scandal forced him to come to grips with his drinking. "Everyone knew me as a fun guy. But lately it had changed. I was not a happy drunk. I became cynical."

Ryan said he can still lead Sheboygan, a city of 49,000 residents on the western shore of Lake Michigan about midway between Milwaukee and Green Bay.

Ryan's seven challengers include high school senior Asher Heimermann, Alderwoman Jean Kittelson, and Terry Van Akkeren, who ran unsuccessfully against Ryan in 2009 and who is the father of a sitting alderman.

If a candidate gets 50 percent of the vote plus one, they would be declared the winner. If no candidate wins a majority on Tuesday, the top two vote-getters will take part in a run-off election on February 21.

Thousands of voters are expected turn out for the election and hundreds of absentee ballots have been cast. The polls close at 8 p.m. local time.

Ryan was a city councilman before winning election to his first term as mayor in 2009, defeating Juan Perez, Wisconsin's first Latino mayor, in a primary.

The recall election is a first for Sheboygan, but not the first time residents have attempted to recall a city leader. Opponents tried to recall Perez six years ago, but failed to gather enough support among voters to force an election.

On Monday night, Ryan locked the door to his office and walked into the darkened third-floor hallway after a council meeting, finding his way by the light from a cell phone.

The phone rang. It was his wife, Mary, calling to find out why he was late. "I haven't had a drink in months, but in the back of her head ...," Ryan said.

(Reporting By Geoff Davidian; Editing by David Bailey and Paul Thomasch)