Drivers take a left turn over the lake and into history, parking their cars on a floating garage modeled after a vintage aircraft carrier. Children's squeals fill an indoor water park that, at 80,000 square feet, would be one of the world's largest.

And a new venue has been carved out for a joy that had been increasingly difficult to find at the giant entertainment complex ? just looking at the lake.

Officials of the Metropolitan Pier & Exposition Authority, which oversees the lakefront attraction, today embraced that vision of the future, saying they could decide to move ahead with the grand plans within a year, and could complete the overhaul in three to seven years.

As first reported in the Tribune last week, the plans made public at the authority's board meeting today could cost hundreds of millions of dollars, at least as much as the $187 million renovation that created the current pier in 1995. The Metropolitan Pier and Exposition Authority, known as McPier, was created by the Illinois General Assembly in the 1980s to operate the pier and the McCormick Place convention center.

Its officials today declined to talk about how a second makeover would be financed until a decision is made on what will actually be built.

Pier officials said the massive water park, monorail, floating parking garages and new marinas were ideas that were all up for debate. In 1995, the state financed the bulk of the renovations.

"Navy Pier is a huge success story, and we've built a lot of momentum," said General Manager Tim Macy. "We've got to continue to build that momentum."

By almost every measure, Navy Pier has been a tremendous success, drawing in 2? times more visitors than were expected before the new tourist spot opened 11 years ago. Navy Pier today attracts nearly 9 million people a year and generates sales of about $138 million.

Yet 60 percent of the visits take place during a short window during the summer. Pier officials want more visitors during seasons when most people instead turn their shoulders to the lake. They also want those people to stay longer.

Last year, the McPier board hired an outside consultant, Forrec Ltd. of Toronto, a designer of theme parks, water parks and other entertainment facilities, to develop a proposed master plan for enhancing the pier's layout, traffic flow and revenue.