A Coast Guard icebreaker carrying 1,200 Christmas trees intended for poor families in Chicago docked Friday next to Navy Pier — continuing a tradition laced in joy and tragedy that began more than a century ago.

The Mackinaw, a modern, steel-hulled behemoth, stars in the annual reenactment of a journey from Michigan to Chicago that was originally made by a wooden schooner named the Rouse Simmons.

In the late 1800s and early 1900s, the three-masted Rouse Simmons carried trees offered at a price affordable to Chicago’s working poor — or for free if people couldn’t pay.

At its helm was Herman Schuenemann, a big-hearted merchant who was proud to be known as “Captain Santa.”

The yearly arrival of the ship, with a tree strapped to the top of its main mast, was highly anticipated.

Then the boat sank during a storm while headed to Chicago on Nov. 23, 1912.

Crowds gathered along the waterfront in Chicago didn’t know. They waited in vain.

When the boat didn’t arrive, a sad little girl in the crowd told her father “Without Christmas trees, there is no Christmas.”

A newspaper reporter heard the exchange and used the quote from the girl. Her name was Ruthie Flesvig.

The sinking of the “Christmas Ship” became the stuff of Lake Michigan lore — and 78 years later captured the imaginations of a group of Chicago sailors who wrote a script and turned it into a play.

Chicago attorney Dave Truitt — who’s also an avid sailor — played the role of Captain Schuenemann.

“We didn’t think anyone would come, and when we opened the doors there were 200 people,” Truitt, 87, recalled of the play they performed at a venue in Streeterville.

“After the play, someone said, ‘Ruthie is here in a wheelchair’ — and it was the little girl, but now she was an old woman,” Truitt said.

“I didn’t know what to do, but then it came to me. I stayed in character and broke off a branch of a Christmas tree that was on stage and walked over to her and said, ‘Ruthie, this is long overdue, but I just want to give you this tree,” he recalled.

“There wasn’t a dry eye in the place, including me,” he said.

The moment stuck with Truitt, who decided to resurrect the “Christmas Ship.”

A group of his sailor pals started a nonprofit and raised money to buy thousands of Christmas trees. The charity was dubbed “Chicago’s Christmas Ship.”

Truitt used connections he had with the Coast Guard and struck a deal under which a Coast Guard ship — between carrying out seasonal buoy maintenance duties — would make room to transport trees from Michigan to Chicago, where they would be distributed through other local nonprofits.

The first batch of trees was delivered in 2000. The 20th batch arrived Friday on the “Christmas Ship.”

On the journey, the Coast Guard lays a wreath in Lake Michigan along the route where Schuenemann’s ship sank in 1912. A crew of 16 lost their lives. The boat was last seen near Two Rivers, Wisconsin.

“There were also three other ships that went down in that storm,” said Coast Guard Cmdr. John Stone, who captains the Mackinaw.

“We wanted to recognize all of the mariners, all of the ships that have gone down in the perils of the Great Lakes,” he said of the wreath laying.

Editor’s note: The Coast Guard is offering free tours of the Mackinaw from 1:30 to 3 p.m. Saturday. The ship is docked just north of Navy Pier.