WINTER HARBOR, Maine — For 100 years and counting, the small fleet of Knockabout sloops that has evolved into a Winter Harbor nautical icon has been put through its paces in weekly regattas that the boats’ well-heeled owners seem to take more seriously than the Dow Jones industrial average.

Built in 1906-07 for the pleasure of the residents of Grindstone Neck by Massachusetts boatbuilders Burgess & Packard, the scattered-to-the-winds, nine-vessel fleet was tracked down decades ago through some crafty detective work. Once reunited they were meticulously restored under the watchful eyes of two Grindstone Neck colony patriarchs, the late F. Eugene “Fitz” Dixon and skipper Alan Goldstein, the current keeper of Knockabout bragging rights.

“These boats are exactly as they were when they were built,” said Sam Heffner, the Winter Harbor Yacht Club’s commodore and the owner and skipper of “Whippet,” a Knockabout that underwent 4,500 hours of restoration at the Maine Maritime Museum’s apprentice shop in 1998-99. “If someone who sailed my boat in 1907 came aboard to sail it today, everything would be exactly the same as then.”

There are two series of Knockabout regattas each summer, held like clockwork every Saturday at 2 p.m. — one series in July, the other in August. Wind speed and direction and other weather conditions determine each regatta’s course, with 12 options that vary in distance from three to five miles. Conditions permitting, there are two races every Saturday, although wind has been a scarce commodity this summer.

“Depending on the wind and the weather, we try to get in at least five races each month, and we count the times for the best four and throw out the worst time for each month’s series,” said Windsor Coffin, who skippers “Mystery” and oversees the logistics of each week’s regatta. “For the season, we count every single race. The overall winner gets their name on a trophy and a year’s worth of bragging rights.”

The competition is fierce, and apparently always has been, Heffner says. “Even 100 years ago this started out very competitive,” he said. “It was vicious. Skippers would ram other boats and run each other into the rocks. I think that’s why they called them ‘Knockabouts,’ as they knocked one another around pretty good.”

For the weekly races, each boat has a four-person crew. “On a gentle weather day, two people can handle these boats, if they know what they are doing,” Heffner said. “But it really takes two people just to handle the jib properly.”

A real estate developer from Baltimore, Heffner pilots a Citation jet that he flies in and out of the Hancock County-Bar Harbor Airport in Trenton when he’s summering in Winter Harbor. The corporate jet cruises at 410 knots.

“I like to say about my Knockabout that I’ve never had more fun at six knots,” he says. “Although the wind has been so scarce this summer that it’s more 2½ knots.”