According to the Duluth Yacht Club, it was one of their racing boats, out for the season's first regatta, which was canceled after weather changed. 

They say the sailboat was heading back to dock, when things went wrong fast.

From the patio outside of Grandma's, Addy Scrimgeour said she and her guests saw a lone sailboat on a crash course with Duluth's lift bridge. 

"It started coming in and I noticed it right at those pine trees and there was just, it was not stopping," she said.

Lift Bridge supervisor Dave Campbell says the skipper called in for a lift, after the wind and current shifted in the lake.

"He was just getting ready to lift when the sailboat hit the bridge," he said.

At the time, Campbell said there was an east wind about 45 knots and a strong inbound current.

"The wind may have blown them into the bridge, but it was actually the strength of the current that pulled them underneath the bridge, " he said.

That's why he said the bridge is equipped with lights on its towers.

"There's always a current in the canal, and if the boat's captain isn't aware of which way the direction of the current, and how strong the current, they can get caught in it," he said.

Red signifies a current headed towards the bridge, yellow is neutral, green is a current headed away from the bridge and a flashing light means the current is especially strong.

He said he wasn't sure if the light was flashing Wednesday evening but he current did get strong fast.

"It started hitting the bridge it just stopped dead in the water but the bottom of the boat kept moving," Scrimgeour said.  "People were starting to fall towards the water, so it was really scary because we thought for sure someone was going to go in."

Fortunately no one did. Once the mast broke, the boat drifted under the bridge, and was able to make it safely to shore.

"That was when I was the most relieved," Scrimgeour said.

The incident called for no emergency response, left no damage to the bridge, but for the skipper it's likely a costly repair and a harrowing story.

According to the Duluth Yacht Club, everyone on board the sailboat is okay, but the club is working on an inquiry to find out what happened.