How many will compete, and how will local harbors fit them all in?

The Race to Mackinac began in 1898 with five yachts competing. It was not held again until 1904 and was put on hold again from 1917 to 1920, owing to World War I. It has been ongoing for 87 consecutive years now, since 1921, and annually sees about 300 boats competing.

In past races, the largest number of boats competing in one year was 325, set in 1998, but, owing to this year's historic emphasis and cooperation between the Chicago Yacht Club and marinas in Mackinaw City and St. Ignace, the club was able to attract more boats.

The race begins Saturday with a parade of boats at Navy Pier from 10 a.m. to 2 p.m. Boats will begin the race between 10 a.m. and 3 p.m. 1.5 miles from Navy Pier, grouped in departures at 10- to 40-minute intervals, with the first boat expected to arrive in the Straits area Tuesday, July 22. The event will be capped off by fireworks on Mackinac Island Tuesday at dusk.

The finish line is a line set up between the yacht club's Island headquarters at Windermere Point and the Round Island Lighthouse.

The biggest buzz about this year's race has been the number of competitors, said Race Coordinator Amanda Matta.

"That's been the biggest question from racers is how many will be competing," she said. "The next question is how we're fitting them all in."

That project was handed to yacht club Vice Chairman Greg Freeman and a small committee, who mapped out the Island's harbor using paper and stickers at the Chicago clubhouse.

"We were literally crawling on our hands and knees mocking up how to fit 400-something boats in the harbor," said Mr. Freeman, who will be in his 23rd Chi-Mac race with the Chicago-based 42- footer Salsa, on which he serves as navigator for the crew. "We've spent hundreds of hours figuring it out. We've put a lot of time and thought into this."

Mr. Freeman said the club has had tremendous volunteer support for this year's race, with about 60 people lined up to help at both ends.

In the past, the docking scheme was simply to raft boats side to side as they came in, said Mr. Freeman. This year, the club has split the harbor into zones and will assign each boat to a docking spot based on the size of the boat.

"Everyone should have a good idea where to park when they radio in at the finish line," he said. "We've never done this before, but I'm confident it will work."

For those boats that dock at the mainland, the club has set up transportation to the Island via special ferry departures on Shepler and Arnold Transit boats Monday and Tuesday evening. At 11:30 p.m., a Shepler's ferry will depart from Mackinaw City and an Arnold Transit ferry will depart from St. Ignace. Both ferries will then depart from the Island and return to their mainland destinations at midnight.

Planning for this year's race began last July and, by December, the club had reached 460, the maximum number of boaters that facilities in the Straits of Mackinac can accommodate. By Tuesday, July 8, the list of registered boats had dropped to 439.

"We've never turned away anyone in past races, but this year, because everyone wants to be a part of this historical event, we had to turn away 80 boats," said Chicago Yacht Club Chairman Greg Miarecki.

Yachts will raft off the 76-slip Mackinac Island marina and between the Arnold Transit dock and coal dock.

About 100 boats will be docked at St. Ignace and up to 35 will be moored at Mackinaw City.