OLD ORCHARD BEACH — Participants in the 30th annual Family Sand Sculpture Competition at Ocean Park tackled the challenge with serious tools, but the combination of pails, shovels, rakes and hoes produced as much fun as anything else Sunday afternoon.

They came from across the United States, Canada and the Atlantic Ocean to be a part of traditional July Fourth festivities hosted by the Ocean Park Association. Most had definite plans to fulfill this year’s theme, “Treasures in the Sea,” and maybe take home a prize.

Competitors included John Fust, 44, of Ottawa, Ontario, who grew up in Montreal and has been coming to Old Orchard Beach all his life. Now, Fust and his family live most of the year in Switzerland, where he is head coach of EHC Visp, a professional hockey team.

While some participants planned their sculptures for weeks, Fust and his wife, Rosalind, decided over the weekend that they and their three children would join the contest. Their massive sea turtle was nearly finished when Fust divulged the secrets of their anticipated success.

“You just need to have a plan, be organized and have fun,” Fust said.

Tradition is a major factor in the contest. Ann Handley of Andover, Massachusetts, has been coming to Ocean Park since she was in college, and competing in the sand sculpture event since 2004.

“In 2008 we came in third,” said Handley, a writer and marketing professional. “We’ve been trying to do that again or maybe even best ourselves ever since.”

The rules for team makeup are pretty loose, but each group must include at least one child. Handley’s team was made up of 22 family members ages 4 to 64, who came from as far away as Washington state, Arizona and Florida to spend the holiday weekend in two family homes in Ocean Park.

A key member of Handley’s team was nephew Ben Higingbotham, 5, of Oak Harbor, Washington, who was having an especially good day Sunday after losing his first tooth. Ben offered the details on the family’s evolving sculpture, dubbed “Aunt-lantis” for all the aunts on the team.

“We’re making a castle you can walk in,” Ben explained. “We’re going to paint it and carve some stuff on it and it’s gonna have a bridge.”

Sculptures were judged on artistic ability, originality, design detail, use of space and special effects, said Katie Lawson, 19, director of Ocean Park’s recreation hall. Lawson is from Westford, Massachusetts, but she has spent summers in Ocean Park since she was a kid.

“It’s a very relaxed beach thing,” Lawson said of the contest. “There are some pretty competitive people, though.”

Each winner received a pail and shovel with other sand sculpture-making equipment. The McElhinney family came in second place with a mermaid sculpture and the Gordon family came in third place with a colorful pirate ship flying an American flag.

The first-place sculpture, “Heracleion,” was created by the Belanger family and friends, a team that included members of five Ocean Park families. The group was headed by Scott Belanger and his daughters, Gabby, 14, and Charlotte, 9, who are fifth-generation Ocean Park residents.

The Belangers started developing a design to fit the theme about a month ago, said Scott Belanger, who is safety director at the General Dynamics plant in Saco. “I’m a stickler,” Belanger said. “You gotta stick with the theme.”

But it was originality and attention to detail that likely pushed the Belangers ahead of the pack.

Heracleion is an ancient city near Alexandria, Egypt, the ruins of which are located in Abu Qir Bay under 30 feet of water. Named by the Greeks for Heracles, a mythological hero, the city of many treasures and statues was found in 2000 by French underwater archaeologist Franck Goddio.

The sand sculpture depicted the towering hero with deeply cut abdominal muscles and a costume made of shells and driftwood sticks.

“I knew a lot of people wouldn’t know who it was,” Gabby Belanger said. “We wanted to make sure we did something original.”