During Ray Keefe’s first polar plunge fundraiser — held about 15 years ago — he recalls it was just him and his then 9-year-old daughter, Maddie, who dove into the icy waters of the Atlantic Ocean.

Oh, how times have changed.

On Saturday, Keefe said he and Maddie were joined by approximately 200 people who braved the frigid waters off the coast of Seabrook for the 15th annual Keefe Family Polar Plunge.

The 200 courageous plungers were joined by another roughly 200 onlookers who lined the beach to watch the spirited spectacle, according to Keefe.

Keefe said it’s a record turnout for the annual event. He pointed out this year’s plunge raised roughly $60,000 for Eddie McMahon, a 17-year-old Lowell boy who is battling brain cancer.

“Great kid and a great family,” Keefe said.

In June 2022, an MRI led to the discovery of Eddie’s tumor, which was then surgically removed. A biopsy determined the tumor was a grade 4 glioblastoma, described by the American Association of Neurological Surgeons as a fast-growing and aggressive brain tumor.

The entirety of the tumor was removed during the surgery, but Eddie’s family learned the teen would need to undergo radiation and chemotherapy treatment, with the hopes of preventing the cancer’s return. They also learned Eddie would require an MRI of his brain periodically for the rest of his life to check for any possible regrowth.

Eddie completed his third round of chemotherapy treatments the week before Christmas.

The teen, a senior at Greater Lowell Technical High School, was honored by Saturday’s turnout.

“It was really cool to see all of the people come out in support for me, driving for 40 minutes up to the beach just to jump in freezing water,” he said.

The National Centers for Environmental Information showed the temperature of the water off the coast of Seabrook was approximately 40 degrees on Saturday.

No big deal for Keefe, now a seasoned veteran of the polar plunge. He described the water on Saturday as “actually pretty warm.”

Of the polar plungers was Eddie’s father, Ed McMahon, a retired Lowell police officer. McMahon pointed out he didn’t do anything to prepare for the chilly dive, such as taking an ice bath or a frigid shower ahead of time.

“It’s the first time I think I’ve ever been above my ankles in that ocean,” McMahon said. “I have trouble trying getting into it in August.”

Ed and his wife, Vicky McMahon, and their other son, 15-year-old Colby, were at the event, along with lots of other family members, and many of those they knew and those they didn’t.

“The sea of love,” Ed McMahon said. “The support was incredible. Guys I worked with 20 years ago were there with their wives and their kids. The giving, the caring, the generosity. It was unbelievable.”

Keefe’s idea of using an annual polar plunge to raise money for local families was born following a 2008 car crash that killed Mark Frattaroli, a 16-year-old Lawrence Academy student. At the time, Keefe’s son was also attending school in Groton, at the Groton School. Keefe wanted to do what he could to support the Frattaroli family.

Each year the polar plunge turnout grows bigger.

“It’s not just about the money,” Keefe said. “It’s about the spirit, it’s about people showing up, it’s about knowing a lot of people there and not knowing them, but they’re all there for you anyhow.

“It was a great day,” he added about Saturday. “That’s why we’ll do it again next year.”