Casco Bay is calm now, but it won’t last.

This weekend, the waters outside Portland Harbor will host a 50-sailboat parade, sailing races, lobster boat races and a tugboat muster – all part of the annual MS Harborfest Weekend.

The event is a major fundraiser for the Greater New England Chapter of the National Multiple Sclerosis Society, and is expected to draw thousands of spectators while raising more than $100,000.

Multiple sclerosis is a chronic, often disabling disease that attacks the central nervous system. Symptoms range from numbness to paralysis and loss of vision.

During the MS Harborfest, money is raised through event registrations, corporate sponsorships and an auction. There’s no admission charge to watch any of the events.

The roots of the fundraiser run deep. The MS Regatta — the sailboat portion of the weekend on Saturday — is in its 32nd year. Other events have been added over the years to the point that the fundraiser now fills an entire weekend.

“We’ll probably have 10,000 people watching and participating for the whole weekend, so it’s a pretty big deal for us,” said Sue Tidd, director of development in Maine for the charity’s Greater New England Chapter. “We just keep adding more and more to it.”

The tugboat muster was added more than a dozen years ago and features tugboats “racing” at their top speeds of about 15 mph, as well as a head-to-head pushing competition, with tugs pushing against each other.

“It’s nice for us to get the general public involved in what we do every day,” said Brian Fournier of Portland Tugboat, who will be in charge of the tugboat Andrew McAllister on Sunday. “It’s basically boys with their toys, showing which (tug) is the strongest, which is the fastest. But none are really that fast.”

The MS Harborfest weekend kicks off Friday evening with a fundraising auction at Portland Yacht Services, featuring items donated by local businesses and artists.

On Saturday, the “parade of sail” will take place around 10:45 a.m., with sailboats traveling from Mackworth Island in Falmouth to the Casco Bay Bridge between Portland and South Portland.

More than 50 sailboats, each at least 20 feet long, will participate in the parade, said Jody Cady, coordinator for the MS Regatta and a crew member for one of the sailboats.

The races will begin at 12:30 p.m. Saturday on three courses stretching from Portland Harbor north to Falmouth and south to Cape Elizabeth. Cady said all the sailboats are owned by recreational sailors.

“For a lot of people, this is the only race they’ll do all year, and we’re happy to help anyone who has never raced before,” said Cady, adding that most race because it’s for a good cause.

Events on Sunday begin at 9 a.m. with a 5K road race that begins at Fort Allen Park on Portland’s Eastern Promenade. The Prom is also a prime viewing spot for the sailboat races on Saturday, as well as the lobster boat and tugboat races on Sunday.

The lobster boat races will begin around 10 a.m. Sunday off the Ocean Gateway terminal in Portland’s East End. The races are expected to attract some 40 lobster boats and are part of Maine’s lobster-boat racing season that begins in June in Boothbay. This will be the 10th race of the season.

The tugboat muster and races will begin around 1 p.m. Sunday and are best viewed from the Maine State Pier.

Ten or so tugboats will parade in the harbor, then race, and finally square off in head-to-head pushing matches to see which tug is the strongest.

“Those tugs churn up a tremendous amount of water,” said Cady. “It’s pretty impressive.”

Staff Writer Ray Routhier can be contacted at 791-6454 or at:

rrouthier@pressherald.com