If not for the Santa hats and singing, the large crowd that gathered at Mystic Seaport Museum's McGraw Quadrangle could have been mistaken for a presidential stump speech or a popular uprising.

Instead, it was the museum's 72nd year of hosting the Community Carol Sing. Sunday's late afternoon event was led by Jamie Spillane, an associate professor of music and director of choral studies at the University of Connecticut. Spillane acted as part-conductor, part-soloist and part-master of ceremonies for the festivities.

A volunteer at the main entrance counted 1,115 attendees from 1:30 p.m. on, although that number doesn't account for the people who filtered in to tour the museum. Before the 4 p.m. sing-along, the Mystic Seaport Carolers performed a holiday concert at the adjacent Greenmanville Church.

Most everybody in the quadrangle showcased an impressive array of holiday apparel. One man wore a slim Santa hat stretching maybe 3 feet above his head. The jolly public faced the Thompson Exhibition Building terrace, which was turned into a stage on Sunday. A grand-sounding choir of 30 or more backed by a powerful brass quartet made Mystic feel like a Christmas movie (and not for the first time, judging by the Hallmark Channel's track record).

Charlie Atkins of Ashford said he and his wife have been coming to the carol sing for about 15 years. Each time, he surrenders himself to Christmas cheer.

"The carol singing is what sparks me to be here," Atkins said. "You come in, you're immediately in the Christmas spirit."

Heather Ainslie, associate director of volunteer services at Mystic Seaport Museum, highlighted the results of the concert: Participants are encouraged to bring cash or canned goods to be donated to the Pawcatuck Neighborhood Center, which offers a range of services such as a community food pantry and a weekend backpack food program for children.  

Ainslie also noted an oft-repeated theme of Sunday's event — the good weather. Spillane credited the favorable conditions for attracting the immense crowd of carolers.

Spillane, who called himself a "Mystic boy," said he's conducted the singalong since 1986, but started attending the event in 1963.

"Events like this really create community that we don't find in any other place," Spillane told onlookers. "I remember there being 400 or 500 people in the '70s, now there's two or three thousand!"

According to Spillane, the choir he directs only rehearses once a year. It comprises Ledyard High School graduates, as Spillane taught there, some current and former UConn students, and local folks, such as his father, who have been singing with the choir for years.

The Mystic Seaport Carolers aren't the only singers who performed on Sunday. Students from Stonington Middle School also took the stage to rapturous applause from the audience.

Songs spanned the religious — such as "Hark the Herald Angels Sing" and "Silent Night" — to festive — such as "Jingle Bells" or "White Christmas."

Beth Kirmmse and her 9-year-old son, Will, said they come to the concert every year. Will said his favorite song to sing is "Frosty the Snowman," while Beth's is "Silent Night."

Kirmmse said a gaggle of family and friends usually come along, but this year she sent clips of the concert she recorded to those who couldn't make it from California, Georgia, Guam and Denmark, among other locations.

A small child stood on the ground in front of the stage past 4 p.m., as daylight dwindled, and some people trickled out to beat traffic, imitating Spillane and conducting the musicians to a crescendo. Even as the crowd thinned, the more dedicated remained, and sang and cheered louder and swayed harder than they had the previous hour.

Spillane said he couldn't remember a sing-along as hard to leave as this one.

He explained why after the concert, as he stood in the nearly empty quadrangle.

"Because it's a huge crowd and everyone's comfortable, it builds on itself," Spillane said. "Our big years when we're 3,000 or so, they support themselves because everyone starts to sing out more, there's more of a feeling of community, and then we can create a lot more joy."

s.spinella@theday.com